ASQ Six Sigma
Short Description
Download ASQ Six Sigma...
Description
Workshop on Structured Problem Solving Using DMAIC Methodology
Agenda
Day 1:
TQM
Introduction to Six Sigma
Define Phase
Project Charter
Day 2:
Seven QC Tools
Process Mapping
Day 3: FMEA Process Capability Control Charts Day 4: Lean Enterprise Day 5: VSM Exercise NTPC Case Study Exam & Wrap Up
The Evolution of Quality • Provides a framework for understanding the history of the quality movement. • Expands the definition of quality. • •
Juran’s Definition of Quality Defined as “fitness for use” based on: • Customer’s perceptions of product design. • Degree to which a product conforms to design. • Product’s availability, reliability, and maintainability. • Available customer service.
ISO Definition of Quality • Degree to which a set of characteristics fulfills requirements Requiremen ts: Convenienc e and speed
Crosby’s Definition of Quality
• Quality is conformance to requirements. • Requirements are answers to key organizational questions: –How quickly will orders ship? –What is our return policy? –What forms of payment are acceptable?
Quality Evolution: Medieval Guilds
Guilds: uDeveloped strict rules for products and services. uUsed stamps to identify flawless goods.
1 2 0 0
Quality Evolution: Product Orientation
uMaster
craftsmen trained apprentices. uIndustrial Revolution divided trades into specialized tasks; inspectors guaranteed quality. uTaylor system increased productivity; inspection departments found defects.
1
2
0
0
Quality Evolution: Process Orientation
uProcesses became uShewhart identified
critical. statistical
quality control. uDeveloped strict rules for products and services. uQuality became relevant for process, not just product.
1
2
0
0
Quality Evolution: Wartime
uQuality
became a safety
issue. uThe military developed a sampling inspection system and trained suppliers.
1
2
0
0
Quality Evolution: Total Quality Movement
uDeveloped
in response to Japanese quality movement. uFocused on improving all processes through people who used them.
1
2
0
0
W. Edwards Deming Quality keys: • Understanding customer needs • Process improvement • Statistical analysis • Expertise of workers • PDCA cycle •
Joseph M. Juran Quality keys: • Features that satisfy customers • Freedom from deficiencies • Juran Trilogy®
– Quality planning – Quality control – Quality improvement
Kaoru Ishikawa Quality keys: • Company-wide participation • Quality control circles • Advanced statistical methods and tools • Nationwide quality control promotion
Armand V. Feigenbaum Quality keys: • Total quality control • Integration of quality development, maintenance, and improvement • Focus on internal and external customers •
Genichi Taguchi Quality keys: • Quality should be designed in. • Quality should minimize deviations from a target. • DOE optimizes performance.
Philip Crosby Quality keys: • Conformance to requirements • Prevention • Zero Defects • Price of nonconformance •
Total Quality Management
Total quality management (TQM):
• A management approach • Centered on quality • Based on company-wide participation • Aimed at long-term success • Through customer satisfaction
3 Cs of TQM
1
Customer relationships
2
Continuous improvement
3
Company-wide participation
Customer Definitions 1
Levels of Customer Satisfaction 1
Noriaki Kano identified three levels: • Expected quality • Desired quality • Excited quality
Customer Feedback 1
Has two parts: ◆ Efforts to capture what customers say about company’s products/services ◆Efforts to drive feedback back into organization
Partnering with customer: ◆ Extension of listening to customer feedback ◆ Most direct route to customer satisfaction
PDCA 2 • A well-known model for continuous process improveme nt is the Plan-DoCheck-Act cycle.
A
Company-Wide Participation 3
• Leadership must come from management. • All employees must be involved. • Employee involvement usually requires employees to work in cross-functional teams.
Employee Involvement 3
Benefits • Improved productivity and cost reduction • Increased participation and job satisfaction • Opportunities for professional development
Barriers “It Won’t Work Here” Perception of loss of management authority Employees feeling “used” “Flavor of the month”
• •
• •
Quality Benefits
• Tangible – Increase in earnings – Decrease in waste – Increase in productivity
• Intangible – Customer goodwill – Alignment between business activities
W. Edwards Deming on Quality • Meeting customer needs + wants = quality. • Quality improves products/services and processes. • Improved products/services and processes = profitability.
A Quality Approach Benefits . . . Organizations
Employees
Customers
Suppliers
Society
Benefits to Employees Pride in products and services Job satisfaction Improved communications Streamlined work processes Happier customers Strong customer relationships Greater job security/benefits
Benefits to Organizations
Quality Studies and Standards Released the Profit Impact of Market Strategy (PIMS) study. Partnered with the Baldrige recognition program. Both organizations support the link between quality and profitability.
External and Internal Customers
Publication Department
Sales Department
Customer
Benefits to Customers Quality results in: • Increased choices. • Improved goods and services. • Expectations met or exceeded.
Benefits to Suppliers • Achievement of performance requirements • Streamlined processes • Efficient communication • Increased customer satisfaction
Benefits to Society
Economic growth and stability
Increased employment opportunities
Product safety
Process Management Quality improvements are applied to single processes within manufacturing. Quality improvements are applied to all organizational activities through process management.
Organizational Process
Introduction to Six Sigma
What is Lean Six Sigma? Introduction • Six Sigma goal is process perfection through defect reduction. • Lean goal is cycle time reduction through elimination of waste. “Only those companies that eliminate their defects will have what it takes to win.” “Breakthrough companies strive for 100 percent DEFECT-FREE products and services.” Larry Bossidy CEO of AlliedSignal
What is Six Sigma? Methodology and Improvement Strategy • •
Six Sigma is an overall strategy to accelerate improvements in processes, products, and services–create breakthrough. Six Sigma measures how effective strategies are in eliminating defects and variations from processes, products, and services.
+
= Y
f(x1,
+ ...
+ x2,
x3
Process output (Y) is a function of (f) the inputs (Xs). Understanding and controlling this relationship is a major aspect of Six Sigma projects.
…)
Focus on Variation • Sigma (σ) refers to standard deviation, a measure of process variation (smaller is better). • Process Sigma is the number of units of standard deviations between the process center and the closest specification limit (larger is better). • A Six Sigma process has six standard deviations (short term) between the target and the closest specification limit. Lower Spec
Target
Lower Process Control Center
Upper Spec
Upper Control
6 Standard Deviations
6 Sigma
Sources of Variation Desig n Materi al
$
Process Capabil ity
Measurem ent System
Harvesting the Fruit of Six Sigma Sweet Fruit
Design for Manufacturability
5 σ Wall - Must Address Designs 5 σ Wall - Must Address Designs
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -4 σ Wall - Must Improve Internally
4 σ Wall - Must Improve Internally
Low Hanging Fruit Seven Basic Tools
----------------------------------
3 σ Wall - Demand improvement 3 σ Wall - Demand improvement
Ground Fruit
Logic and Intuition
The walls crumble faster when working WITH suppliers and CONCURRENTLY addressing design and process issues
da nu ou s Co nti
Process Characterization and Optimization
ta
Bulk of Fruit
D is c r e t e d a ta
The Focus of Six Sigma
• • • • • •
f (X)
Y
Y Dependent Output Effect Symptom Monitor
•X1
. . . XN •Independent •Input-Process •Cause •Problem •Control
Would you control shooter or target to get the Gold Medal at Olympics
Six Sigma Defines Problems Statistically
Y= f (X) The product is used to evaluate the process.
Y - Outputs uDependent uOutput uEffect uSymptom uAble to Monitor
Should we focus on the process outputs (Y) or inputs (X)?
X1 . . . X N Inputs uIndependent uInputs, process uCause uProblem uControllable
The process is used to control the product.
99% Good (3.8 Sigma)
99.99966% Good (6 Sigma)
20,000 lost articles of mail per hour
Seven articles lost per hour
Unsafe drinking water for almost 15 minutes each day
One unsafe minute every seven months
5,000 incorrect surgical operations per week
1.7 incorrect operations per week
Two short or long landings at most major airports each day 200,000 wrong drug prescriptions each year No electricity for almost seven hours each month
One short or long landing every five years 68 wrong prescriptions per year One hour without electricity every 34 years
Define Phase
The Define Phase The define phase module provides an overview of the following tools:
1.Project selection 2.Project charter 3.Supplier, Input, Output, Customer (SIPOC) diagram 4.Collecting Voice of the Customer (VOC)
Projects Must be … Meaningful And Manageable!
Sorting Projects from Messes • A mess is a morass of unsettling symptoms, causes, data, pressures, shortfalls, opportunities, etc. • A problem is a well-defined situation that is capable of resolution • Identifying a problem from within the mess is frequently the first step in the process of project definition •
Project Qualifications • There is a gap between current and desired performance. • The cause of the problem is not clearly understood. • The solution is not predetermined. •
Project Selection is Critical • High leverage projects lead to largest $$ Savings • Large returns justify the investment in time and effort • Developing a Lean Six Sigma culture depends upon successful projects having significant business impact • Black Belt training depends on completion of a meaningful project within ~ 6 months • Future Projects are frequently identified through initial projects •
Lean Six Sigma Project Criteria • Aligned with business objectives and plans – Voice of Customer/ Critical to Satisfaction (CTS) – Quality (CTQ) / Cost (CTC) / Delivery (CTD) • Consistent with principles of Six Sigma – Elimination of process defects – Reduction of variation • Concentrates on significant issues/opportunities ..... not “problem of the day” • Justify the investment •
Project Selection “The best Six Sigma projects begin not inside the business but outside it, focused on the question — how can we make the customer more competitive? What is critical to the customer’s success? … One thing we have discovered is that anything we do to make the customer more successful inevitably results in a financial return to us.” Jack Welch Address to the General Electric annual meeting April 23, 1997
What is Customer Satisfaction? • A comparison of expectation to experience • A matter of degree • A result of a good match between supply and demand • A predictor of repeat business •
Customer Needs Translated into “Critical To” (CT) Characteristics Customer needs are translated into product, service or deliverable requirements in terms of quality, delivery and cost. The “Y” of Y=f(X). Typical Critical to Characteristics
Y
CTQ
Critical to Quality
CTD
Critical to Delivery
CTC
Critical to Cost
Breakdown of • Projects are identified by the relationship between the processes product, service, or deliverable requirements and processes. required to produce the • The process parameters that affect the requirements are later identified (X , X , … X ) product, 1 2 n service, or deliverable. • Leverage processes are identified.
Project Selection Criteria Pain area Faster Deployment
Aligned with core objectives
Stakeholder Satisfaction
Repeatable
High probability of success
Higher returns
Process Improvement Data Availability
S. No. 1 2 3 4
Criteria
Weight
Aligned with core objectives High probability of success Data Availability Pain area
10 10 8 8
5
Process Improvement
7
6
Higher returns
8
7
Repeatable
6
Faster Deployment
5
Stakeholder Satisfaction
7
Ease of implementation
6
8 Ease of implementation 9 10
Project Selection Matrix Diagram Project 1 S. No. Criteria
Project 2
APC Reduction in Boiler (Stage II) stage I Optimization
1
Aligned with core objectives
2
High probability of success
3
Data Availability
4
Pain area
5
Process Improvement
6
Higher returns
7
Repeatable
8
Faster Deployment
9
Stakeholder Satisfaction
10
Ease of implementation
Strong Relationship
Project 3
DM (Stage I) Make up ESP (Stage I) Inlet Optimization Duct Replacement
Moderate Relationship
1 0
Selected Project
Project 4
Project 5 Soot Blowing Sy.Optimization
Weak Relationship
6
3
Factors that Improve Project Success • Dedicated Black Belt • Champion phase reviews • Black Belt has knowledge of process/product to be improved • Historic data • Clearly defined deliverables • Committed process owners (skin in the game) with the authority to modify the process •
Project Metrics – Success Criteria Primary Metric • Used to measure project success • Consistent with the problem description and objective • Plotted on a time series graph and shows the goal and actual performance lines
Secondary Metric(s) • Control unintended negative consequence (assures the Primary Metric is not achieved artificially) • May be used to measure project progress when the Primary Metric responds slowly • More than one may be required • Plotted on a time series graph and shows the goal and actual performance lines
8
Project Charter Traditionally created by LSS Champion Specifies details of a project including:
1.Scope 2.Responsibilities 3.Benefits 4.Schedule 5.Success criteria A project charter template that may be adopted to fit your organization is: Project Charter Template.
SIPOC Supplier, Input, Process, Output, Customer diagrams are used to: 1.Define the scope of the project 2.Identify key stakeholders 3.Gain a “30,000 foot” view of the process targeted by the project Tips: 1.The SIPOC is the first of several ways the process will be documented. Therefore, it should be at a relatively high level of abstraction. 2.It is a good way to assure agreement on the scope of the project.
SIPOC Diagram – Questions to Answer • Who are the customers of this process? • What are their requirements? • How are those requirements reflected in the process parameters (output measures)? • What are the process outputs? • What are the process inputs that cause the outputs? • What controls are in place for the inputs? • Who are the suppliers of the material for this process? • What are their requirements?
Purpose of Various Diagrams / Maps • SIPOC diagrams provide a “forest view” of the process – maintains focus on the customer’s requirements. • Value stream “trees level” describes the time, effort, resources, and information used in the process – a frequent source of early wins. • Lay-out diagram (spaghetti diagram) documents the distance an item travels during its production – illustrates unnecessary movement. • Process map “ground level” documents the inputs and outputs of each step in the process – provides the raw material for building a model of the process. •
The SIPOC Diagram – The Forest Level • • • • • • • • •
Start with the end in mind. Who are the customers of this process? What are their requirements? How are those requirements reflected in the process parameters (output measures)? What are the process outputs? What are the process inputs that cause the outputs? What controls are in place for the inputs? Who are the suppliers of the material for this process? What are their requirements?
Sample SIPOC Supplier(s)
Inputs/Req'ts
Process
Output(s)/Req'ts
Grocery store Utility Company Appliance store
Coffee machine Measuring cup Electricity Qualified operator Water Filters Cream/milk Sweetener Ground coffee
Install filter Measure coffee Add coffee Add Water Turn on machine
1800 Specified number of cups No grounds < one hour old Dark Hot Aromatic Fresh Strong
Customer(s)
Husband Wife Guest
SIPOC Validation Review the SIPOC with your: team, Champion and process owner(s) to assure agreement on the SIPOC content as well as the project scope and success criteria among all stakeholders.
S
I Inputs
Suppliers Coal Field Rihand Dam Suppliers
P
O
C
Process
Outputs
Customers
Coal Water
Power Effluent Process Ash
Air Power
Steam CO2
Manpower Lubricants
Internal -Plant Mgmt -Corp Mgmt -Employee External -Cent.Gov. -Ministry
Maintenance Services Spares and
-State Gov. -Shareholders
Consumables
-Contractors -Suppliers -PAPs -Labour Environment
Boiler Turbine COAL AIR WATER
STEAM
CTQs Plant Availability UI Earned Plant Load factor Heat Rate
AUXILLIARY POWER CONSUMPTION Preferred Employer R&R Man : MW Ratio Lead Time Manpower Utilization Quality System Social Responsibility Maintenance Cost Overhead Expenses
ENERGY EFFICIENCY DM Water Used Safety aspect
Generator
GRID
Training of manpower Cycle Time In process idle stock Air Emission quality Noise level
Collecting VoC • Who is a customer? • What does the customer need? – Gathering the Voice of the Customer – Define customer requirements
• How do the customers prioritize their needs? • How are customer needs translated into CTQs? uGenerally
a less intense exercise for DMAIC projects than for DFSS projects
uMore
likely to be based on information that is already available internally for DMAIC projects than for DFSS projects
Who Is a Customer? Process Voice of Customer
Step
Step
Step
Product/ Service Customer
A customer sets/affects requirements for your product or service. External Buying customers End-users Regulatory agencies A customer is one who receives your output. Internal
Customer Segmentation •Generally, external customer needs are more important than internal customer needs. •Are all customers equally important? –External vs. internal –Customer segments •Regions •Type of business •Volumes •Profitability •Strategic market •Future potential •
Voice of the Customer • The Voice of the Customer (VOC) is the starting point of any project and data collection plan. • The Voice of the Customer includes: – Expectations – Requirements – Opinions
–
Questions to Find Voice of the Customer • What are the elements of your business that are the most critical, from the perspective of your top or best customers? What are their relevant needs? • What data has been collected to understand the customer requirements? • How do you operationally define the defect from the perspective of the customer? Under what conditions does it occur?
Voice of the Customer Concerns • Real vs. stated needs • Perceived needs • Intended vs. actual usage • Internal customers vs. external customers • Effectiveness vs. efficiency needs • Change over time
Determining Customer Requirements • Use verbatim comments from customers to help determine the key customer requirements – We often receive many verbal comments from our customers. – We need to look for ways to probe for deeper meaning behind the comments in order to translate these comments into what the customer actually requires.
•
Tools for Gathering Voice of the Customer
Unsolicited data from customers – Complaints – Field reports – Trade journals – Benchmarking – Internal research • • • •
•
Requirements documents Contracts Customer observation Be a customer
Tools for Gathering VOC Solicited data from customers
– Interviews – Focus groups – Surveys – Informal customer discussions – Market research
•
Determining Customer Requirements • Review customer verbatim comments and comparative data • If possible, probe for deeper understanding • Convert into terms of process performance • Describe the actual customer requirement – Write the requirement, not the solution – Use measurable terms – Identify performance targets – Be concise
Define Phase Review • The purpose of the define phase is to identify and launch a project. • VOC should be reflected in the project charter especially in the project success criteria. • The Black Belt and Champion should review and agree on the details of the project charter and SIPOC. • A common cause of project failure is poorly defined or projects with excessive scope. This review is an opportunity to mitigate that risk.
D M A I C
VOC ( Voice of Customer )
Generation & Dispatch
Environmental Pollution Conservation of Coal
RATING
5 5 4 4
5 5 4 4 4 5 4 2 4 5 4 4 5 5 2 5
81 90 64 66
Better
Same
Competitor Worse
Replace with eff. pro
Systems Better
Arrest Pro.Deviation
Aux Power Consumption
Improve Processes
WHAT ?
CustomerNeed Needs Customer
Ranking ( 1-5 )
HOW ?
D M A I C Project Charter
D M A I C Resource Plan Champion: Process Owner: Process Owner: Quality Leader Coach (BB): Green Belt:
S. Sinha TMD V. Agarwal EEMG
Mr. P.K.Mohapatra Mr. N.N.Mishra Mr. N.K.Sinha Mr. S. Mathew Mr. S. Banerjee Mohit Yadav Iswar BMD Ashish Jain EMD
Green Belt Contact Information :
General Information
Project Review Dates Tollgate
Date
Define
Big Y:
Measure Analyze
Reduction in APC of Stage-I units
Improve Control
Mohit Yadav 9425823299 1550
05/02/ 07 05/04/ 07 15/04/ 07 31/05/ 07 31/08/ 07
Project Team Rhythm and Review Meeting Frequency: Mandatory Attendees: Optional Attendees:
Signoff
(xx/xx/xx)
Yes Yes Yes Yes Yes
Rhythm and Review: On-Track Off-Track Need Attention
15 Days Mohit Yadav
V. Agarwal
Mr. P.K.Mohapatra
Mr. N.N.Mishra
Iswar
S. Sinha
Mr. N.K.Sinha
A. Jain
Mr. S. Banerjee
VOC ( Voice of Customer )
The Seven QC Tools
➨ ➨ ➨ ➨ ➨ ➨ ➨
Check sheet Stratification Pareto diagram C &E Diagram Histogram Scatter diagram Graphs and Charts
v Problem Solving v Continuous Improvement-- Kaizen v Dispersion Control-- Six Sigma v Waste Elimination--Lean v QMS, EMS, TS 16949, OHSAS-Process control, C&P v Supplier Development v Project Management--Team working
What is their role ?
In problem solving
Tool
Role they Play
Data gathering
Check sheet
Stratification
Quantify current status or magnitude of the Problem Facilitate data gathering
Identify and segregate different sources of the problem
•
Tool
• Pareto diagram •
• Brain storming
• Cause & effect diagram
Role they Play
• Prioritize the problem •
• Generate many ideas for solving a specific problem • Identify possible causes of a problem in a structured way •
Tool
Role they Play
• Histogram
• • Scatter diagram
• Study pattern of variation in a set of data. • Study relationship between 2 types of variable
• Visual display of data
• Graph & chart
•
DATA GATHERING
Data Collection
What is Data ? Data is a numerical expression of an activity
Conclusions based on facts and data are necessary for any improvement. K. Ishikawa If you are not able to express a phenomenon in numbers, you do not know about it adequately Lord Kelvin
Types of Data
Quantitative •Measurable e.g. :Length, Temperature •Countable e.g. :Number of defects
Qualitative •Subjective assessment e.g. :Score in a beauty contest
Population, Sample and Data
Action
Population
Random Sampling
Sampl e Action
X
Measurement / Observation
Data
A Saying q When you see the data, doubt it q When you see the measuring instrument, doubt it. q When you see the chemical analysis, doubt it. q Three Categories q
1 False Data 2 Mistaken Data 3 No Data available
How to Collect Data? qDefine the purpose (Follow 5W 1H approach). qDefine the period for data collection. qDefine the Stratification. qDesign the check sheet and assess Measurement System Capability.
Purpos e
Be Clear on What, Where, When, Why, Who and How the data should be generated
STRATIFICATION
Stratification
vMethod of grouping data by Common points or characteristics
v
vA Filtration Process for isolating the cause of a problem.
vPrevent mix up and helps in easy & faster identification-
Basis for Stratification Workers
Machines
Defect
Product Folder
Material Time Environment
Region Files
Machine Machine A A
Machine BB Machine
N = 450 N = 450 D = 12D = 12 P% =P% 2.7= 2.7
N 450 = 450 N= = 118 D =D 1118 P%== 26.2 26.2 P%
COMBINED N = 900 D = 130 P% = 14.4
Blister Defect UCL CL Pinhole Defect UCL C L All Defects
UC L CL
CHECKSHEET
Check sheet
v
A convenient and compact format for data collection
v A Simple rule– Maximum
information with minimum writing
efforts and easy to fill
v
Check Sheet For Machining Operation Location M/C No.
Comp.
DRG. No
Date
Group Token No.
Op.
Qt. Prod. Material Defect No. Insp. 1 2 3 4 5 6
M/c Defects
Total
Remark
A B C D………P Q R
Machining Defect
Material Defect 1: Blow holes 2: Cracks 3: Hard Metal 4: Eccentric 5: Others 6: Total
Shift
A: Dia.+ B: Dia.C: Ch+ D: ChE: CDV+ F: CDV-
G: Length+ H: Length I: Sp+ J: SpK: D& T Size+ L: D & T Size-
M: Oblong N: Taper O: Hole Shifted P: PCDV Q: Poor Finish R: Others
Graphs & Charts Graphs represent data pictorially. A picture can see what 1000 words can not tell. v Line chart v Bar chart v Multiple bar Chart v Component bar Chart v Radar chart
v Pie chart v Gantt chart v Pareto diagram v Scatter diagram v Control chart
v
•
v
v
Bar Chart Bar graphs are parallel bars of identical width but differing length to compare size of different quantities / things.
Line Chart
Line graphs manifest the overall trend in time series data by direction of their lines.
Pie Chart Pie charts makes it easy to grasp the breakdown of the components of a quantity over a certain period.
Comparison of Machines A & B for weekly Rejection
% Rejection
25 21
20
20
15
14
15 11 10
15
13 10
Multiple bar chart
20
11
13 11
10 8 6
5
5
4
3
2
3
0 1
2
3
4
5
6
7
8
9
10
Week Number
Comparison of Machines A & B for Units Produced 900 800
Component bar chart
Units Produced
700 600
400
358 281
317
29 9
375
321
307
29 4
6
7
8
9
336 2 44 221
300
435
200 100
422
257
500
2 63
285
201
2 75 348
1 33
0 1
2
3
4
5
W eek N umb er
10
Pie Chart for Customer returned watches
E 4%
•A – Glass Broken
F 3%
D 6%
•B - Stop •C - Mvt. Trouble
A 43% C 12%
•D - Defective Dial •E - Regulation •F - Stem Loose •G - Others
G 5%
B 27%
Control Chart
X- Bar and R Chart Xbar/R Chart for C1
Sample Mean
2854
UCL=2853
2849
Mean=2849
LCL=2844
2844
Sample Range
Subgroup
15
0
5
10
15
20
25
UCL=16.41
10 R=7.76 5 0
LCL=0
Radar Chart on ISO 9001-1994 Implementation 1 20
80
2
70
19
3
60 50
18
4
40 30
17
5
20 10
16
6
0
15
7
14
8 13
9 12
10 11
Series 1
Gantt Chart for Construction Activity
Weeks
Type of work
1
2
3
4
5
6
7
8
9
10
11
Foundation work Frame work Dry-walling Exterior touch up Sheetrock work Plumbing Electrical wiring Fit Fixtures Paint interior wall Interior touch up Inspection delivery
Gantt Charts makes it easy to understand the details of a plan and progress in its implementation schedule.
12
Pareto Diagram
Vital few from Trivial many 94.6
100
87.5
50
90
76.8
80 70
60.7
60 30
50
41.7
40
20
30 20
10
10 0
0
Fish not Vegetable fresh wilted
Bread Stale
Cashier Rude
Meat not Eggs rotten Fresh
Cum Percentage
Pareto Analysis of Customer Complaints
No. of complaints
40
100
Pareto Principle
v80% of problems are caused by less than 20% of probable causes vEstablishes proof of the need vIdentifies vital few
PARETO ANALYSIS: Outstanding branch wise BRANCH
BRANCH
Rs . DUE
RATIO TO TOTAL
CUM . %
A= 5.0 B= 2.5 C = 10 . 0 D = 20 . 0 E = 45 . 0 F=1.5 G=1.0 H=1.5 87 Oth. 0.= 0 . 5
E D
45.0 20.0 10.0 5.0 2.5 1.5 1.5 1.0 87 0.5.0
51.7 23.0 11.5 5.7 2.9 1.7 1.7 1.2 100 0.6 .0
51.7 74.7 86.2 91.9 94.8 96.5 98.2 99.4 100.0
C A B F H TOTAL G OTHERS
Pareto Analysis on Outstanding
91.9
94.8
96.5
98.2
99.4
100
86.2
50
90
74.7
80 70 60
51.7
50 40
20
30 20
10
10 0
0
E
D
C
A
B
F
H
Branches
G
O
Cum Percentage
Outstanding Value
40
30
100
Pareto Diagram for Production Stoppage 45
90
B.Intermediate conveyor
40
80
C.Power failure
35
70
D.Hopper/duct line jamming
30
60
25
50
20
40
15
30
10
20
5
10
0
0
E.Dryer drum coupling pin F.B P full press problem G.Dryer preventive H.Nip roller I.Rotary comb tripped J.Comber jamming K.Al conveyor idle roller L.Fire M.Accumulation N.Drum seal changing O.Fan tripping P.Chain problem
No. of stoppages
A.M/C quality change
A B C D E F G H I J K L MN O P Q R S
Cumulative %
100
Pareto Analysis of Complaints at a Laundry 93
200
100
85
180
140
80 70
60
120
60
100 80
100 90
75
160 No. of complaints
98
50
35
40
60
30
40
20
20
10
0
0
Late Missing or Fading delivery wrong colours items
Stains
Creased
Buttons Stretched Missing or torn
Brain Storming
generating large number of ideas by a group of people
Basic Rules vDefer evaluation vFantasize freely vGenerate quantity vBuild on ideas •
Defer Evaluation vPut critical faculties in cold storage - even constructive criticism. v vEnsure a proper climate for acceptance of all sorts of ideas. v vNo idea should be treated as stupid.
Fantasize Freely vDon’t operate with your brakes on. v
vParticipants are encouraged to generate ideas, no matter how fanciful they are.
Generate Quantity vGenerate as many ideas as possible. v
vA pearl diver will be more successful in finding pearls, when he brings up 200 oysters than when he surfaces only 1520 oysters.
Build on ideas Idea of one participant is more effectively built up by another participant.
Steps in Brainstorming v Select the topic v v Each member, in rotation gives ideas v v Member offers only one idea per turn, regardless of how many he or she has v v Continue till all ideas are exhausted v v Ideas are recorded and displayed
Benefits v Individual is limited in generating ideas and group produces more ideas v v Ideas are improved upon by members v v Presence of others increases creativity v v Pooling of ideas and resources is made possible by coming together as a group
CAUSE AND EFFECT DIAGRAM
qGraphic tool to represent relationship between an effect and influencing causes qThere can not be an effect without a cause. qReduce incidence of subjective decision making. qIdentify main causes X’s influencing Y
Construction of C & E Diagram v Define problem v Gather members for discussion v Conduct Brainstorming v Group causes into 4M’s v Man, Material, Machine, Method v For each cause, ask, “What goes wrong that produces the effect”. v Identify major causes
Cause and Effect Diagram for high petrol consumption Procedure
Driver
Impatience
Poor anticipation
Craze
Always late Lack of awareness Riding on clutch
Wrong gears
Vehicle
Bad attitude Poor skill
Spark plugs Contacts Life
Heavy Body Shape Inexperience
Wrong culture
High H.P
One way
No turn
Circuitous Road
Road
Fuel mix Carburetor
Engine Cylinders
Restrictions
Technical details
Crossings Traffic
Spares
Spurious
High Petrol
Consumptio n
Impurities Incorrect Octane no.
Tyres Inferior Frequent Petrol Faulty stops Negligence pressure Speed Breakers Additives Ignorance Potholes Irregular Incorrect viscosity Low pressure servicing Poor Clogged Oil condition filters False Steep Not changed economy Low level Maintenanc
e
Materials
Cause & Effect Diagram
PROCESS COOKING TIME
TRAINED
MATERIALS
QTY OF WOOD QLTY COOKING WATER (OLD/FRESH) TEMP. IN PENTOSANS IN FINAL PULP INSTRUMENT UNTRAINED ACCURACY
PERSONNEL
EQUIPMENTS
VARIATION
Uses of C & E Diagram vTrace out real root cause vHelp evolve countermeasures vMaking C & E an education in itself vEveryone participating, learn more about their work. vIs a focus for discussion. vShows level of expertise available. vCan be used for any problem v
v
v
v
v
30 24
25 19
Frequency
20
17
15
12
11
9
10
6 5
3
2
0 1 .7 7 6
1 .8 6 8
1 .9 6
2 .0 5 2
2 .1 4 4
2 .2 3 6
2 .3 2 8
2 .4 2
2 .5 1 2
C o n s u m p ti o n ( K W h )
HISTOGRAM
Histogram vMethod of analyzing data v v
vData is condensed in a table v v
vTabulation is known as frequency distribution. v
vPresented by a Graph displaying distribution of data v
Histogram
Graph is Characterized by 3 constituents
• centre ( mean) • width (spread-variation) • over all shape v
30 24
25 19
Frequency
20
17
15
12
11
9
10
6 5
3
2
0 1 .7 7 6
1 .8 6 8
1 .9 6
2 .0 5 2
2 .1 4 4
2.23 6
2 .3 2 8
C o n s u m p ti o n ( K W h )
2 .4 2
2 .5 1 2
Histogram Construction vSelect a sample of min. 50 vRecord the measurements. vDetermine the range. vDecide the no. of classes. vDivide range into no. of classes vDetermine boundary or class limits. vPrepare frequency distribution. vConstruct histogram (GRAPH).
Data on Metal Block thickness (in mm) 3.56 3.46 3.48 3.50 3.42 3.43 3.52 3.49 3.44 3.50 3.48 3.56 3.50 3.52 3.47 3.48 3.46 3.50 3.56 3.38 3.41 3.37 3.47 3.49 3.45 3.44 3.50 3.49 3.46 3.46 3.55 3.52 3.44 3.50 3.45 3.44 3.48 3.46 3.52 3.46 3.48 3.48 3.32 3.40 3.52 3.34 3.46 3.43 3.30 3.46 3.59 3.63 3.59 3.47 3.38 3.52 3.45 3.48 3.31 3.46 3.40 3.54 3.46 3.51 3.48 3.50 3.68 3.60 3.46 3.52 3.48 3.50 3.56 3.50 3.52 3.46 3.48 3.46 3.52 3.56 3.52 3.48 3.46 3.45 3.46 3.54 3.54 3.48 3.49 3.41 3.41 3.45 3.34 3.44 3.473.47 3.41 3.38 3.54 3.47
Range= Max. – Min.=3.68-3.30=0.38 N=10 0
No. of classes= 9 Class width= 0.5
Frequency Table
Class no.
Histogram for Metal Block Thickness 45 40
37 33
35
Frequency
30 25 20 15
5
10
9
10 3
3
3.3
3.35
3
1
1
3.65
3.7
0 3.4
3.45
3.5 Thickness (in mm)
3.55
3.6
Histogram for Bearing Thickness
45
41
40 35
Frequency
31
29
30 25
22 18
20 15
17
12 9
10 5
5
3
0 5.24
5.28
5.32
5.36
5.4
5.44
Thickness (in mm)
5.48
5.52
5.56
5.6
Histogram for Energy Consumption
30 24
25 19
Frequency
20
17
15
12
11
9
10
6 5
3
2
0 1.776
1.868
1.96
2.052
2.144
Consumption(KWh)
2.236
2.328
2.42
2.512
Types of Histograms Bell shaped Symmetrical shape with a peak in middle representing a normal histogram
–
30
24
25 19
Frequency
20
17
15
12
11
9
10
6 5
3
2
0 1 . 7 7 6 1 .8 6 8
1 .9 6
2 .0 5 2 2 . 1 4 4 2 . 2 3 6 2 . 3 2 8 C o n s u m p tio n( K W h)
2 .4 2
2 .5 1 2
Skewed to Left & Right
Skewed to Left Caused by centering the process toward high end of the tolerance Skewed to Right Caused by centering the process toward low end of the tolerance..
Bimodal & Truncated
Bimodal : Two combined populations-- two shifts, operators, inspectors, suppliers, machine settings, gages, tools, machines, measurement locations, etc. Truncated: This can happen when a process is not capable of meeting the specifications, parts are sorted from both ends, or too few classes are chosen.
Missing Centre Spike's at Tail (s)
Missing Centre : Centre of the distribution has been sorted from the rest. Portion may have been delivered to a customer with tighter specifications. Spike's) at the Tail (s) : Parts in outer ends of distribution are probably being reworked to bring characteristic just within specifications.
The Need for Transformations--Prediction from a ND is possible … Skew distribution Transformation Before
After
XTrans = 1/XRaw
Histogram Uses vTo know--whether variation in data is due to chance or assignable causes. vTo tell about Process Behavior v --about its capability to produce defect free output v v
Sources Of Variation
vCommon Causes ---Chance Causes Of Variation vSpecial Causes --- Assignable Cause Of Variation
Common Cause vConsists of combined effect of several sources of uncontrollable variation inherent to a process. vCollective influence of common cause variation defines natural process fluctuation and is known as Chance causes of variation. vProcess output is predictable vProcess is said to be in Statistical Control v v
Special Cause vVariation has a large impact on performance. vDetermination of source of impact makes cause "assignable." and is termed as assignable cause of variation. vIf they exist, process or key characteristic is said to be "out-of-control". vOut-of-control process is not predictable
Process Behavior vIt tells whether process is under control? vIs it producing defect free output? v ----process under control or
LS L
Process out Of control US L
LSL
USL
30 24
25 19
Frequency
20
17
15
12
11
9
10
6 5
3
2
0 1 .7 7 6 1 .8 6 8 1 .9 6
2 .0 5 2 2 . 1 4 4 2 . 2 3 6 2 . 3 2 8
2 .4 2
2 .5 1 2
C o n s u m p ti o n ( K W h )
process variability
process variability
Good Process Behavior vShape close to normal curve vMean at target value vSpread within Specification limits v
v
v v
vCp is greater than 1.67 and Cpk is greater than 1.33 v
SCATTER DIAGRAM
What: To study the possible relationship between two variables.
Why:
Diagram make it clear whether a
relationship exists, and shows the strength of relationship.
When:To test a theory that the 2 variables are related.
Examples:
vCutting speed and tool life vBreakdown and equipment age vTemperature & lipstick hardness vTemperature and percent foam in soft drinks vHardness and tensile strength
Different Scatter diagram Patterns
Scatter Diagram on Conveyor Speed vs. Severed Length
1050
Severed Length (mm)
1045 1040 1035 1030 1025 1020 1015 1010 1005 1000 5
5.5
6
6.5
7
7.5
Conveyor Speed (cm/sec)
8
8.5
9
Uses: vControl Purpose vReplacing a destructive test by a non-destructive test vStudy of Cause & Effect relationship vProcess Optimization v •
Process Mapping
About This Module… Process Mapping is a tool used to: ◆Clearly define processes ◆ ◆Identify areas where data
collection should take
place ◆ ◆Visualize
activities involved in a process at the early stages of project development
Six Sigma, A Quest for Process Perfection Attack Variation and Meet Goals
\DataFile\ProcessT.ppt
What We Will Learn … 1.The importance of process maps and the character of the product and process parameters. 2.The when, why and where to use process maps. 3. 4.The x’s & y’s and X’s & Y’s and Y=f(x,X). 5. 6.What to measure and control. 7. 8.The need for process maps prior to FMEA’s, Gage Studies, DOE’s and SPC. 9. 10.When the process map is completed. 11. 12.How to use the tool for your process.
Extending Extending Flow FlowCharts Chartsto to Process ProcessMapping Mapping
Process Management Basic Process Model
Resources • • • • •
System
Input Input
People Equipment Material Money Time
A
Process Process C
Output Output P
D
Feedback
Cycle Time • Time it takes to complete a process from beginning to end
Question “How does a reduction in cycle time benefit an organization?”
Fundamentals of Process Mapping AAprocess processmap mapshould shoulddescribe: describe: ◆◆Major Majoractivities/tasks activities/tasks ◆◆Sub Subprocesses processes ◆◆Process Processboundaries boundaries ◆◆Inputs Inputs ◆◆Outputs Outputs ◆◆Process Process&&Product ProductParameters Parameters ◆◆Customers Customers&&Suppliers Suppliers ◆◆Process Processowners owners
AAprocess processmap mapshould shouldbe be reviewed reviewedfrequently frequentlyand andisis never neverdone. done. AAprocess processmap mapshould should document documenthow howthe theprocess process actually actuallyoperates, operates,nothow nothowitit isissupposed supposedto tooperate. operate. (“As (“Asis,” is,”not not“To “ToBe”) Be”) AAprocess processmap mapwill willidentify identify opportunities opportunitiesfor forquality quality improvements. improvements.
Principles of Process Management • Establish ownership. • Verify and describe the purpose of the process. • Define the process, boundaries, and interfaces. • Organize and train the process improvement team.
Principles of Process Management • • • •
Define and document the process. Define points of control. Establish process measurements. Improve process.
Process Mapping Steps 1.IDENTIFY INPUTS AND OUTPUTS –Identify Inputs (raw material, equipment, energy, 6M’s, etc.) –Identify Outputs (measurable/assessable end product parameters) 3.SHOW ALL STEPS –Value adding steps have the following characteristics: uSomething
the customer would be willing to pay for
uTransforms uDone
the product or service
right the first time
–Non value-added steps in the process are presented graphically: uEvaluation uRework uScrap
points
points
points
uInventory
Steps (cont.) 3.SHOW OUTPUTS OF EACH STEP –Show after each process step the characteristics that can impact the following step(s). u
4.SHOW ALL PROCESS PARAMETERS AT EACH STEP –List under each step the parameters that can change a product characteristic at that step (i.e., parameters that can be controlled at that step). u
More Steps 5.CLASSIFY THE PARAMETERS –Classify the process parameters identified (in #4 above) into the following categories: u
N = Noise Factors - Uncontrollable - May be controllable, but are not controlled by decision. C = Controllable factors - Process factors that can be changed to see the effect on product characteristics. S = Standard Operating Procedures - A procedure is used to define and run those factors. Tooling, Fixtures. ✔ CR = Critical Factors - Determined through FMEA, DOE, etc.
Inputs & Outputs High Level Process Map X’s
Y’s
INPUT S
OUTP UTS
PROCESS
Processes Come in Hierarchies Process - Level #1 Step #1
Step #2
Step #3
Process - Level #2 Step #1
Step #2
Step #3
Process - Level #3 Step #1
Step #2
Step #3
Select Selectthe theappropriate appropriateprocess processlevel. level.
Product and Process Parameters STEP OF PROCESS
Inputs
Process Parameters, x’s
Outputs
y = f(x)
Remember the 6 M’s ◆Man
(People)
◆Machine ◆Method
(Equipment)
Product Parameters, y’s
(Procedures) KEY for (x’s) Process Parameters
◆Material ◆Measurement ◆Mother
Nature (Environment)
N C
Noise Parameters Controllable Process Parameters S SOP Parameters CR Critical Parameters
Why List the Parameters? TO REDUCE DEFECTS! ◆The
Defects
x’s and X’s are the sources of variation in your process.
◆Variation
causes defects.
◆The
x’s must be under control to prevent defects.
◆The
root cause of a defect is variation of the x’s!
◆The
y’s and Y’s are the measured results of the process and include the failure modes of the process.
◆Defects
are also outputs of a process step.
What Are We Measuring? Measure the x’s, not the Y’s !
X’s
Inputs _________ ?
x’s
Process Parameters _________ ?
y’s Y’s
Process Step Outputs
_________ ? Process Outputs
_________ ?
We Wecannot cannot control controlwhat what we wedon’t don’t measure! measure!
Is Workmanship an x? Y’s
X’s INPUT S
OUTP UTS
PROCESS Process Parameters, x’s
y = f(x)
WORKMANSHIP ?? OPERATOR ?? ✚ 6 M’s reminders: ◆Man
(People)
◆Machine ◆Method
(Equipment)
(Procedures)
◆Material ◆Measurement ◆Mother
Nature (Environment)
Product Parameters, y’s ◆DEFECT
FREE OUTPUT
◆DEFECTS
◆
IN PROCESS OUTPUT
What Are the x’s and y’s? Y’s
X’s Inputs 6 M’s reminders: ◆Man
(People)
◆Machine ◆Method
(Equipment)
(Procedures)
◆Material ◆Measurement ◆Mother
Nature (Environment)
Outputs Process Parameters, x’s N N N N C C
KEY for (x’s) Process Parameters N C
Noise Parameters Controllable Process Parameters S SOP Parameters CR Critical Parameters
y = f(x)
C C S S
Product Parameters, y’s
Identifying Product & Process Parameters The following may be helpful to identify process parameters that have a potential effect on the product parameters and process output: ◆Brainstorming ◆Literature
review
◆Operators ◆Work
manuals
Instructions
◆Operator
experience
◆Customer
/ supplier input
◆Engineering ◆Scientific
knowledge
theory
Remember the 6 M’s ◆Man
(People)
◆Machine ◆Method
(Equipment)
(Procedures)
◆Material ◆Measurement ◆Mother
Nature (Environment)
Completeness Checks Inputs
Step of the Process
Outputs
y = f(x)
Process Parameters, x’s Are there y’s for every x in this step? Is there a “good” type of y for every x ? Is there a “bad” type of y for every x ? Are x’s here that impact downstream y’s? Does the map have input of extended team?
Remember the 6 M’s ◆Man KEY for (x’s) Process Parameters N C
Noise Parameters Controllable Process Parameters S SOP Parameters CR Critical Parameters
(People)
◆Machine ◆Method
(Equipment)
(Procedures)
◆Material ◆Measurement ◆Mother
Nature (Environment)
Product Parameters , y’s ◆Good ◆Bad
= Defects ◆Good Rejected = Defect ◆Bad Accepted = Defect ◆Horror Stories: What has happened in the past that caused disasters? ◆Success Stories: What outputs of this step thrilled the customer(s)? ◆Are there x’s for each y in this step? ◆Are upstream x’s changing y’s of this step? How?
Wave Solder Process LOAD IN FIXTURE
INPUT X’s £Boards with components £Solder £Flux £Electricity £Machine Setup
LOAD ON CONVEYOR
❑Masking ✖Operator ✔Board thickness ✔4-Corner support ✔Bd. Spacing in Fixture ✔Bd quantity in fixture ✔Bd. position within fixture Front or rear Side ✔Fixtures/conveyor width ✔Bd Orientation ✚Frame size/Board size ✚Fixture mass. ✚Fixture dimensions ✚Vert. location bd.in fix. ✚Component Orientation ✚Component Density
❑Conveyor speed ✖Rail position over pot ✖Conveyor angle ✔Time req’d in Solder ✚4-Corner Fixture support ✚Conveyor drive smoothness ✚Finger condition ✚Rail Straightness
Bd Orientation Bd Spacing Bd Alignment Bd to Rail Position Critical areas masked
Current Setup: Specifications Flux: Kester 2% Solid FACTOR S.G.: NA RANGE NOMINAL
Pre Heat #1 Temperature 400
FLUX AIR KNIFE
FLUX ✖Pressure ✔Flux Brand ✔Flux Type ✔Thinner ✔Cleanliness of flux ✔Tritration level ✔Stone Type ✔Cleanliness of Stone ✔Height over Stone ✚Temperature ✚Humidity ✚Ambient Temp
Immersion depth Raised Carrier Frame corner Poor wetting ⇒Partial filled holes ⇒Skip Soldering ⇒Bridging ⇒Excessive solder speed ⇒Insufficient solder ⇒Bridging ⇒Cycle Time
TO PREHEAT
❑Pressure of air knife ✖Orientation ✖Distance to board ✖Air Knife used ✔Angle of air knife ✚Temperature
Solder in all holes Solder Bridging Solder Insufficients Fire Qty of Excess Flux
Lead Solderability Amount on Bd. Flux through holes to top side Distribution on Bd. KEY for (x’s) ⇒ Excessive Solder Process Parameters ⇒ Bridging ✚Noise Parameters ⇒ Icicles ✖Controllable Process Parameters ✔SOP Parameters ⇒ Partially filled Holes qCritical Parameters Cleanliness of Board
Pre Heat #2 Pre Heat #3 Solder Emmersion Conveyer Temperature Temperature Temperature Depth Speed 2.75-4.25 445 470 490 1/4" 3.75
Angle N/A
Hot Air Knife Angle 45-65 60
Pressure 12-20 17PSI
Wave Solder Process (cont.) PREHEA T #1
PREHEA T #2
❑Temp - Zone 2 ❑Temp -Zone 1 ✖Temp - Zone 1 ✖Temp - Zone 2 ✖Temp -Zone 3 ✖Temp - Zone 3 ✖Time in Preheat 2 ✖Time in Preheat 1 ✖Resp time of heater ✖Resp time of heater ✚Stability of temp ✚Stability of temp ✚Dist to board ✚Distance to board ✚Temp distribution ✚Temp distribution ✚Fixture warp ✚Fixture warp ✚Rail warp ✚Rail warp
Board Temp Flux Condition Flux Activated Flux Solvent drive off Thermal Shock ⇒ Board Warping Excess Heat ⇒ Excess Solder ⇒ Poor Fillets ⇒ Excess flow thru Inadequate Heat ⇒ Solder splatter ⇒ Trapped Gas ⇒ Solder Bridges ⇒ Poor flow thru (plated thru holes)
PREHEA T #3 ❑Temp - Zone 3 ✖Temp - Zone 1 ✖Temp - Zone 2 ✖Time in Preheat 3 ✖Response time of heater ✚Stability of temp ✚Distance to board ✚Temp. Distribution ✚Fixture warp ✚Rail warp
Board Temp Flux Condition Flux Activated Flux Solvent drive off Thermal Shock ⇒ Board Warping Excess Heat ⇒ Excess Solder ⇒ Poor Fillets ⇒ Excess flow thru Inadequate Heat ⇒ Solder splatter ⇒ Trapped Gas ⇒ Solder Bridges ⇒ Poor flow thru (plated thru holes)
HOT AIR KNIFE
SOLDER POT ❑Solder Temp ✖Ht of Pot/Position ✖Solder Pot Angle ✖Exit Point ✖Amount of dross ✔Solder Pump Speed ✔Solder Height ✔Solder Pump Pressure ✔Choke bar setting/adj ✔Solder contact ✔Solder type ✔Solder tin content ✔Solder Contam ✔Baffle qual, hole wear, bent condition, clean ✔Board Deflection
Board Temp Flux Condition Flux Activated Flux Solvent drive off Thermal Shock ⇒ Board Warping Excess Heat ⇒ Excess Solder ⇒ Poor Fillets ⇒ Excess flow thru Inadequate Heat ⇒ Solder splatter ⇒ Trapped Gas ⇒ Solder Bridges ⇒ Poor flow thru (plated thru holes)
✖Position ✖Dist to board ✔Temp ✔Angle ✔Air Pressure ✚Temp Dist .
Solder Distribution Coverage on board Solder Appearance Solder joint Quality
KEY for (x’s) Process Parameters ✚Noise Parameters ✖Controllable Process Parameters ✔SOP Parameters qCritical Parameters
EXIT WAVE SOLDER ✖Workmanship Stds ✖Samples ✖Lighting ✖Magnification ✖Prod/Dmnd/Sch ✖Census/Inspection Staffing ✖Inspection Sample . (%) ✚Eyesight ✚Inspector Variation
I N S P E C T I R O NE W O R K
OUTP UT Y’s Boards: •Accepted •Rejected •Scrap
y’s Product Paramenters
Excess Pressure ⇒Solder Bridging ⇒Insufficient solder/Opens Insufficient Pressure ⇒Solder Bridging Temp Too Low ⇒Solder Bridging Temp Too High ⇒Insufficient Solder/Opens ⇒Damage Board Angle Too Steep ⇒Insufficient Solder/Opens Angle Too Shallow ⇒Solder Bridging
Solder Appearance Solder Joint Quality/Defects Open Solder Joints Good Boards Dirty Boards Scrap Boards Hot Boards Damaged Components Lifted Components
The Importance of Questions Noise Parameters: ◆What
are they? ◆Are they impossible or impractical to control? ◆How robust is the system to the noise? ◆
Controllable Parameters: ◆How
are they monitored? ◆How often are they verified? ◆Are optimum target values known? ◆How much variation is there around the target values? ◆How consistent are they? ◆
Standard Operating Procedures: ◆Do
they exist? ◆Are they understood? ◆Are they being followed? ◆Are they current? ◆Is operator certification performed? ◆Is there an audit schedule?
Process Parameter Questions Process Parameters: ◆What
causes variation of the process parameter? ◆How is the process parameter controlled? ◆How often is the parameter out of control? ◆Is there data on the parameter? ◆Which of your process parameters should have control charts on them? ◆When should you place a control chart on a process parameter? ◆Which of your process parameters have control charts on them? ◆How are the control charts used? ◆How do you know which process parameters to monitor? ◆Should we focus on parameters of non value-added steps?
Product Parameter Questions Product Parameters: uWhat uIs
is the goal of the improvement effort?
the product parameter qualitative or quantitative? –An attribute or a variable?
uFor
the product parameters: –Is larger better? –Is nominal best? –Is smaller better? –Is it dynamic in nature?
uIs
the concern for... –Process centering? –Process variation? –Both?
uWhat
is the process baseline for the product parameter? –What is the mean and sigma?
More Product Parameter Questions Product Parameters: ◆Is
the product parameter currently in statistical control? ◆Is the product parameter affected by time? ◆How much of a change in the product parameter do you need/wish to detect? ◆Do you know the expected distribution of the product parameter? ◆Is the measurement system adequate? ◆Are there multiple responses of concern? What are the priorities for optimization? ◆What measurements are taken on product parameters? ◆How do you know which product parameters to monitor? ◆Which product parameters need control charts on them? ◆Which product parameters have control charts on them? ◆How are the control charts used?
Process Map-Flow Charting (Step-by-Step) Identify the inputs and outputs of the process
Document entire flow of the process selected
Identify all value and Non value-added operations
Identify/classify the scope of the process
Identify/classify measurements taken on product & process parameters
Continue to update & classify process map!
Classify/ characterize process parameters into 3 main factors
rNoise factors rStandard operating procedures rControllable process parameters
Develop initial list of process parameters along with current operating conditions
Identify/classify upstream in-process product parameters
Consider Every Process Step 1. What Process work is a process ◆All processes have owners ◆All processes can be described as a verb and noun ◆All processes can be analyzed and improved
feedback
◆All
Requirements
2. What Output 3. What Input
4. Who are Customers 6. Who are Suppliers
feedback
8. Process Controls/Dependencies Procedures/Policies Any written document that controls/impacts a process
5. What Customer
◆Process
owner’s requirements on the supplier ◆Specifications ◆Cost ◆Schedule
◆Specifications
–Function –Reliability –Format ◆Cost ◆Schedule
7. What Supplier Requirements
Training/Education
Equipment/Facilities
Quality Attitudes
◆Performance
◆Space
Personal attitude which is less than the requirement
skills ◆Certifications
required
◆Processing
equipment
Causes of Process Map Failure CONCERN
RESPONSE
Requires extra effort - “We know the process - lets just move forward”
Initial payoff is team understands process -- team members are not working on different set of assumptions. Use experts to help you through the mapping process
The process appears straight forward - then becomes difficult as you realize you do not understand process as well as you thought
If necessary, adjust process boundaries -- initiate another improvement team
The process map just seems to grow and grow and grow
Think about approaching the problem hierarchically
Process Mapping Summary What Whatisisthe thetool? tool? ◆◆Graphical method to illustrate Graphical method to illustrate the thedetails detailsofofaaprocess process ◆◆
What Whatwill willthe thetool toolidentify/show? identify/show? ◆◆All process steps, value-added All process steps, value-added &&non nonvalue-added value-added ) ◆◆Input Inputparameters parameters(X (Xi,in i,in ) ◆◆End Endproduct productparameters parameters(Y (Yi)) i
◆◆In-process parameters (x’s & In-process parameters (x’s &
y’s) y’s) ◆◆Characterization of all Characterization of all parameters parameters ◆◆Defect/data collection points Defect/data collection points ◆◆Steps needing FMEA’s Steps needing FMEA’s ◆◆Sources of variation identified Sources of variation identified
When Whendo doyou youapply applythis thistool? tool? ◆◆Always: to fully understand Always: to fully understand process process&&process processflow flow ◆◆Find where/when/how defects Find where/when/how defects are arebeing beingcreated created ◆◆Define elements of cycle time Define elements of cycle time ◆ ◆
What Whatresults resultscan canyou youexpect? expect? ◆◆Systems needing MSE’s Systems needing MSE’s ◆◆List of Factors for DOE’s List of Factors for DOE’s ◆◆Find the hidden factory Find the hidden factory ◆◆Opportunities for process Opportunities for process step stepelimination elimination(i.e. (i.e.flow flow improvement) improvement) ◆◆Ways to re-layout the process Ways to re-layout the process ◆◆Sources of variation reduced Sources of variation reduced
Map Your Process For the next session: • Map and characterize a critical part of your process. • Identify: – The Inputs (X’s) – The Outputs (Y’s) – The Process Parameters (x’s) – The Product Parameters (y’s) – The process owner, supplier, & customer – Classify the parameters at each step – The next step to reduce defects in your process
What We Have Learned … 1.The importance of process maps and the character of the product and process parameters. 2.The when, why and where to use process maps. 3. 4.The x’s & y’s and X’s & Y’s and Y=f(x,X). 5. 6.What to measure and control. 7. 8.The need for process maps prior to FMEA’s, Gage Studies, DOE’s and SPC. 9. 10.When the process map is completed. 11. 12.How to use the tool for your process.
Extending Extending Flow FlowCharts Chartsto to Process ProcessMapping Mapping
Failure Modes and Effects Analysis FMEA
About This Module… Failure Modes and Effects Analysis
An FMEA is a systematic method for identifying, analyzing, prioritizing and documenting potential failure modes, their effects on system, product, process performance and the possible causes of failure. Six Sigma, A Quest for Process Perfection Meet Goals and Attack Variation
\DataFile\FMEAform.xls \DataFile\CopyFMEA.xls |Datafile|causeeffecte.igx \Datafile\catapultflow.igx \Datafile\catapultC&E.igx
What We Will Learn… Failure Modes and Effects Analysis 1. As a Team, how to construct an FMEA and associated Action Plan 2. How the FMEA process ties to process mapping 3. The relationship between Failure Mode, Cause and Effect 4. The different types of FMEAs Ü
Sample FMEA S Failure E Effects V Causes Must redo copy 6 Paper Jam Must redo copy Must redo copy
Must redo copy Must redo copy Must redo copy Must redo copy Must redo copy
O D R C E P C Controls T N
Action Recommended
Periodic Maint. 7 294 Periodic preventive maintence Place sign over copier outlining Existing standard size enlarge/reduce or User notes on reliable mach to clearly indicate 6 misset size 6 copier 5 180 standard reduce/enlarge User Existing misset notes on Place sign to encourage user to 6 control 5 copier 4 120 utilize auto settings Used landscape instead of portrait or Tray Place note on ruler re tray 6 vice versa 7 Selection 2 84 selection
6
6
align marking not clear Doc moved when lid closed
7
Resp. Schedule Person Date
Key Opr
3/1
Action Taken PM Schedule created and implemented
Key Opr
2/20
Key Opr
Actual Compl. p p p Date S O D
p r p n
R i Risk s X k prpn
2/15
6 3 7 126 3 378
Place sign over mach
2/15
6 3 2
36 1
36
2/20
Place sign over mach
2/15
6 2 2
24 1
24
Key Opr
1/20
Placed Note
1/15
6 2 1
12 1
12
Use Auto Feeder / Enlarge marks for 8.5 " paper on 4 align ruler 3 72 ruler Key Opr
1/15
Enlarged marks
1/14
6 2 1
12 1
12
Use Auto Place sign over copier re Feeder / "Ensure align prior to copying or 5 align ruler 2 60 use auto Feeder" Key Opr
1/15
Displayed Sign
1/14
6 1 1
User selected wrong tray 3
Auto select 6 function 3 54 Periodic Cleaning 6 Dirty Glass 6 SOP 1 36
Place sign over copier to encourage user to use auto tray select
Key Opr
2/25
Place sign over mach
2/20
6 2 3
Place cleaning material near copier
Maint.
1/15
Placed Cleaning Matl
1/15
6 1 1
Datafile/CopyFMEA.xls
6
1
6
36 1
36
6
1
6
Why Use FMEAs? What is an FMEA? Identify critical product characteristics and process variables Prioritize product and process deficiencies in support of downstream improvement actions Help focus on prevention of product and process problems
Benefits of FMEA’s What is an FMEA?
F u Helps increase customer satisfaction. M u Reduces product development timing and cost. E u Reduces the amount of rework, repair and scrap. u Documents and tracks actions taken. A u
Improves the quality, reliability and safety of products.
u
Prioritizes deficiencies to focus improvement efforts.
Process and FMEA Hierarchies What is an FMEA? Process - Level #1 Step #1
Step #2
Step #3
FMEA - Level #1
Step #3
FMEA - Level #2
Process - Level #2 Step #1
Step #2
Process - Level #3 Step #1
Step #2
Step #3
FMEA - Level #3
Process FMEA Steps What is an FMEA? uSteps
Completed Prior to FMEA:
–Charter Team –Develop and Characterize Process Map
uFMEA Steps:
1.Identify “Heavy Hitter” Process Step
1. 2.
3. 4. 5. 6. 7. 8. 9. 10.
1.Identify Associated y’s (Product Parameters) 1.Identify Failure Mode 1.Identify Failure Effects/Rate Severity 1.Identify Causes/Rate Occurrence 1.Identify Controls (if any)/Rate Detection 1.Calculate RPN 1.Prioritize by RPN Order 1.Determine Actions/Plan 1.Recalculate RPN Based on Plan 1.Take Action
FMEA Form What is an FMEA?
Header Accessible from View Header/Footer in Excel
Workbook in Excel
\DataFile\FMEAForm.xls
Cause -Failure Mode -Effect Continuum What is an FMEA?
Effect (y’s) Cause (x’s)
Failure Mode
The Cause and Effect Diagram Example What is an FMEA? Admin/Service Example Measurements
Materials
First produced in 1950 by Professor Kaoru Ishikawa Also called the: uIshikawa Diagram uFish Bone Diagram
Manpower
Failure Mode (Defect)
Mother Nature
Methods
Machines
Failur e Effec t
Developed to represent the relationship between some “effect and all possible “causes” influencing it. Create using Igrafx:
The Cause and Effect Diagram Example Cause and Effects Diagram Measurement Manpower Inadequate training
Material
Reproducibility
Repeatability
Late
Linearity
Wrong quantity Lack of experience
Stability Calibration
Defective
Distractions
Defects Too hot
Vague
Too humid Not maintained Too cold
Inadequate capability
Out of date Complex
Mother nature Machines
Methods
Datafile/Causeeffecte.igx
Copy Machine Example What is an FMEA?
• Our process is copying documents on a Xerox model XC1045 copy machine. • First we will construct a process map • Then we will construct a cause and effect diagram • Finally we will complete an FMEA
Process: Making A Copy What is an FMEA?
Make Copies
Place Document in Copier
Set number of copies
N Hinges N Glass clean
C Copies required Cr Number button
Document set correctly Glass clean
Legend C Controllable Cr Critical N Noise P Procedure x Input
Enter size required C Size desired Cr Size button
Number of copies selected correctly
Set light/dark settings
Select paper source
C Darkness desired
Size selected correctly
Press button
C Size desired x Paper
Darkness set directly
Retrieve copies
Cr Button
Correct paper tray selected
Copies
Copies Right number Right contrast Right orientation Right size Right paper
Step 1: Identify “Heavy Hitter” Process Step The FMEA Process uFrom
the Process Map, identify the process step with the most likelihood of having failure modes with significant effects
defect data and/or team knowledge about failure F modes when selecting process steps impact to the business? (COPQ, cycle time, fill M uSignificant rate, ...) E uUse a Cause and Effect Diagram to capture brainstorming results. A uAfter completing FMEA Steps #2-7 for all failure modes uUse
associated with this process step, return to this step and select the next most likely “Heavy Hitter” process step
uNot
all process steps will need to be analyzed by the FMEA
Step 2: Identify Associated y’s The FMEA Process uFrom
the Process Map, identify the y’s that are associated with the process step being investigated
uAs
the y’s are the indications of a successful completion of the process step, they are crucial as a basis for determining failure modes
Step 3: Identify Failure Mode The FMEA Process • Brainstorm failure modes for the selected process step : – Identify the ways in which the process could fail to generate each of the expected “y’s” • Eliminate “duplicates” from brainstorm list • Are the failure modes from the same level of the process? • Are the failure modes specific? • Are the failure modes the most likely? • Do the failure modes provide good coverage of the process step? • Have all y’s been considered?
Step 4: Identify Failure Effect/Rate Severity The FMEA Process uPick
the most likely failure mode and brainstorm the most important Effects: –FAILURE EFFECTS are the outcome of the occurrence of the failure modeon the process. The impact on the customer --- What does the customer experience as a result of the Failure Mode?
uIdentify
each effect as being “Attribute” or “Variable”
uSeverity
doesn’t change unless the design changes.
Step 5: Identify Causes/Rate Occurrence The FMEA Process uIdentify the most likely causes for each failure mode using a Cause and Effect Diagram: –CAUSES are the conditions that bring about the Failure Mode uTransfer
the resulting information to the FMEA form
uAssign
an occurrence value (1-10) to the likelihood that each particular cause will happen and result in the failure mode
uThe
occurrence score for each cause should be related to the likelihood of that cause resulting in the failure mode and producing the specific associated effect
Organize Brainstorming Ideas The FMEA Process Measurement Wrong Size Selected
Materials
Manpower Selected wrong orientation
Wrong Paper Size
Copy Misaligned Too Humid
Mother Nature
Document Moved When Lid was Closed
Method
Alignment Marking Unclear
Machine
What would you add?
Step 6: Identify Controls/Rate Detection The FMEA Process uIdentify
the current mechanisms in place which prevent the causefrom occurring, or detect it before the product reaches the customer. Some examples of controls are SPC, training, maintenance, inspection, SOP etc.
uAssign
a detection value (1-10) based on an assessment of the likelihood that the current control mechanisms will detect the cause of the failure mode before it reaches the customer.
uDon’t
agonize over detectability.
Step 7: Calculate Risk Priority Number The FMEA Process The product of the estimates of severity occurrence and detection. The RPN provides a relative priority for taking action the bigger the RPN, the more important to address.
RPN = SEVERITY x OCCURRENCE x DETECTION
Steps 8 and 9 The FMEA Process 8: Prioritize by RPN Order Use the “Sort” command in Excel to order the spreadsheet in descending order of Risk Priority Number (RPN). 9: Determine Actions/Plan Based on the causes found, determine actions that will minimize the effect of each cause, in priority order.
Steps 10 and 11 The FMEA Process 10: Recalculate RPN Based on Plan uAssuming the actions are carried out successfully, reassign severity, occurrence and detectability. u
uPlace
these new ratings in the “predicted” columns (ps, po & pd).
u
uAssign
a rating from 1 to 5 for each action that will show the “risk” associated with each action (5 being the greatest risk). Place the rating in the “risk” column.
11: Take Action uBased on the risk mitigation column (Risk * prpn), take the actions indicated or reassign actions. Then…. u
uComplete
the actions indicated by the times stated!
The FMEA Process Steps 1-11:
Step 2 ID y’s
Step 1 ID Process Steps S Failure E Effects V Causes Must redo copy 6 Paper Jam Must redo copy Must redo copy
Must redo copy Must redo copy
Step 6
Step 4 O D R C E P C Controls T N
7
Step 9
FMEA Action Recommended
Periodic Maint. 7 294
Periodic preventive maintence Place sign over copier outlining Existing standard size enlarge/reduce or User notes on reliable mach to clearly indicate 6 misset size 6 copier 5 180 standard reduce/enlarge User Existing misset notes on Place sign to encourage user to 6 control 5 copier 4 120 utilize auto settings Used landscape instead of portrait or Tray Place note on ruler re tray 6 vice versa 7 Selection 2 84 selection
align marking 6 not clear 4 Doc Must moved Step redo 3 when lid copy 6 closed ID Failure Modes 5
\DataFile\CopyFMEA.xls Step 11
Resp. Person
Schedule Date
Key Opr
3/1
Action Taken PM Schedule created and implemented
Key Opr
2/20
Key Opr
Actual Compl. p p p Date S O D
p r p n
R i Risk s X k prpn
2/15
6 3 7 126 3 378
Place sign over mach
2/15
6 3 2
36 1
36
2/20
Place sign over mach
2/15
6 2 2
24 1
24
Key Opr
1/20
Placed Note
1/15
6 2 1
12 1
12
Use Auto Feeder / Enlarge marks for 8.5 " paper on align ruler 3 72 ruler Key Opr
1/15
Enlarged marks
1/14
6 2 1
12 1
12
Use Auto Place sign over copier re Step Feeder / "EnsureStep align prior 7 to©ing or align use auto Feeder" 5 ruler 2 60
8
Step 10 Key Opr
1/15
Displayed Sign
1/14
6 1 1
6
1
6
Process FMEA Types of FMEA • Helps analyze manufacturing and assembly processes to reduce the occurrence and F improve detection of defects. • Assists in the development of process control M plans. E • Establishes a priority for improvement activities. • Documents the rationale behind process A changes and helps guide future process improvement plans. • IS PROACTIVE! Should be started when new processes are designed or when old processes are changed.
Process FMEA Scoring Definition Types of FMEA Score 10 9 8 7 6 5 4 3 2 1
SEVERITY CRITERIA Hazardous Without Warning Hazardous With Warning Very High High Moderate Low Very Low Minor Very Minor None
OCCURRENCE 1 in 2 Very High 1 in 3 Very High 1 in 8 High 1 in 20 High 1 in 80 Moderate 1 1 in in 400 Moderate 2,000 Moderate 1 in 15,000 Low 1 in 150,000 Low £1 in 1,500,00 Remote
DETECTION Absolute Uncertainty Very Remote Remote Very Low Low Moderate Moderately High High Very High Almost Certain
Note: When completing a Process FMEA, first assume the material is good and the process is bad. Then assume that the process is good and the material is bad. Lastly, review the process for safety considerations.
Design/Product FMEA Types of FMEA
F M E A
• Helps to identify potential product failure modes early in the product development cycle. • Increases the likelihood that all potential failure modes and their effects on assemblies will be considered. • Assists in evaluating product design requirements and test methods. • Establishes a priority for design improvement. • Documents the rationale behind design changes and helps guide future development projects. • IS PROACTIVE! Should be done when new products are designed or existing products are changed.
Defect FMEA Types of FMEA
• F • M• •
E A
Helps identify the root causes of defects. Establishes a priority for improvement activities. Documents plan of action. Provides methodology to battle initial ground swell of defects. • Focuses effort on defects with highest $ impact. • IS NOT PROACTIVE!
Scoring Criteria Types of FMEA Score 10 9 8 7 6
SEVERITY CRITERIA
Use actual defect quantities
OCCURRENCE
DETECTION
Hazardous Without Warning Hazardous With Warning Very High High Moderate
Very High Very High High High Moderate
Absolute Uncertainty Very Remote Remote Very Low Low
5
Low
Moderate
Moderate
4 3 2 1
Very Low Minor Very Minor None
Moderate Low Low Remote
Moderately High High Very High Almost Certain
Note: To change header information, click on "View" then "Header". RISK: Optional field used to reflect the probability of completing actions.
The Catapult FMEA Exercise Analyze the Catapult process using the FMEA tool. (Remember we want to get the “most bang for the buck”.)
• • • • • •
Break into the Catapult teams We have already constructed a process map First, we will construct a cause and effect diagram Then we will complete at least two failure modes for the most critical step(s) of our process Appoint a spokesman for your team to debrief the class on your progress, questions, etc. Complete the FMEA (FMEAform.xls) for the Catapult process before the third session (We will use this information for our DOE competition)
25 minutes!
Catapult Process Map FMEA Exercise Start
Assemble Catapult Pins (2) Arm Rubber Band Ball
Clamp Tape Measure Tape
Arm moves smoothly
Pull Arm to Proper Angle
Positions Designated
Feasible settings
Measure distance
Tape Measure Observers positioned properly
Operator Lateral movement Correct angle
Set Catapult Pins
Plan or Prediction equation Computer
Aligned with tape ± 3 inches
Shoot
Operator Consistency No Parallax
Select Catapult Settings
Secure to table
Ball flys straight
Correct settings
Record distance
Stop
Recorder Computer
Accurate measurement ± 2 inches
Correct distance recorded
Datafile/Catapultflow.igx
Complete the Diagram Below FMEA Exercise Men Method Calculation procedure
Material Release consistency Rubber Band Ball
Angle measurement
Distance Air Conditioner
Arm moves freely
Repeatability Reproducibility
Mother nature Machine
Measure
Datafile/CatapultC&E.IGX
When To Update an FMEA? FMEA Summary An FMEA should be updated whenever a change is being considered to a product’s: u
design
u
application
u
environment
u
material
u
product’s manufacturing or assembly process
Summary of Product/Process FMEA’s FMEA Summary u What is the tool?
uWhen
–Spreadsheet –
–When evaluating product for robustness (functionality, produceability, reliability) –During early stages of defect reduction efforts to identify causes –When identifying key process/product parameters and evaluating methods for controlling them –
uWhat
will the tool identify/show? –All product/process failure modes, related effects, causes, & methods of controlling them –Risk Priority Number (RPN) for action based on failure severity, probability of occurrence and detection capability –Actions/plans to reduce elements of RPN
do you apply this tool?
uWhat
results can you expect? –Learn to identify critical product/ process parameters –Achieve consensus on solutions and methods of implementation –Detailed product/process understanding
Keys to Success FMEA Summary uIdentify purpose...BE SPECIFIC! u uUnderstand effects...INVOLVE CUSTOMERS & SUPPLIERS! u uLink to the process map. u uUse to prioritize efforts, allocate resources. u uUse as a risk assessment/prioritization tool based on predicted u uUse to build consensus on prioritization. u uEncourage creativity...TEAMWORK! u uPLAN! u uASK QUESTIONS!
impact.
Process FMEA Steps What is an FMEA? uSteps
Completed Prior to FMEA:
–Charter Team –Develop and Characterize Process Map
uFMEA Steps:
1.Identify “Heavy Hitter” Process Step
1. 2.
3. 4. 5. 6. 7. 8. 9. 10.
1.Identify Associated y’s (Product Parameters) 1.Identify Failure Mode 1.Identify Failure Effects/Rate Severity 1.Identify Causes/Rate Occurrence 1.Identify Controls (if any)/Rate Detection 1.Calculate RPN 1.Prioritize by RPN Order 1.Determine Actions/Plan 1.Recalculate RPN Based on Plan 1.Take Action
FMEA Appendix Key Definitions for FMEA Severity is an assessment of how serious the effect of the potential failure mode is on the customer. The customer in this case could be the next operation, subsequent operations, or the end user.
Occurrence is an assessment of the likelihood that a particular cause will happen and result in the failure mode.
Detection is an assessment of the likelihood that the current controls (design and process) will detect the cause of the failure mode, should it occur, thus preventing it from reaching your customer. The customer in this case could be the next operation, subsequent operations, or the end user.
Current Controls (for both design and process) are the mechanisms which prevent the cause of the failure mode from occurring, or detect the failure mode, should it occur, before the product reaches your “customer.” For example, current controls include SPC, inspections, written procedures, training, preventive maintenance and all other activities that ensure a smooth running process.
Critical Characteristics are those items which affect customer safety and/or could result in non-
compliance to regulations and thus require controls to ensure 100% compliance. These are usually process“settings” such as temperature, time, speed, etc.
Significant Characteristics are those items which require SPC and quality planning to ensure acceptable levels of capability.
FMEA Appendix Terminology A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P. Q. R. S. T.
Process or Product Name – Description of Process or Product being analyzed. Responsible – Name of Process Owner. Prepared By - Name of Agent coordinating FMEA study. FMEA Date – Dates of Initial and subsequent FMEA Revisions. Process Step/Part Number – Description of individual item being analyzed. Potential Failure Mode – Description of how the process could potentially fail to meet the process requirements and/or design intent, i.e. a description of a non-conformance at that Potential Failure Effects – Description of the effects of the Failure Mode upon the customer, i.e. what the next user of the process or product would experience or notice. SEV (Severity) – An assessment of the seriousness of the effect of the potential failure mode Potential Causes – Description of how the failure could occur, described in terms of something OCC (Occurrence) – Description of how frequently the specific failure cause is expected to Current Controls – Description of process controls that either prevent, to the extent possible, DET (Detection) – An assessment of the probability that the current controls will detect the potential cause, or the subsequent failure mode. RPN (Risk Priority Number) – The product of the Severity, Occurrence, and Detection Rankings i.e., RPN = SEV * OCC * DET. Actions Recommended – Actions to reduce any or all of the Occurrence, Severity or Detection rankings. Responsibility – Person or group responsible for the Recommended Action. Actions Taken – Brief description of actual action and effective date. New SEVERITY Rating after corrective action. New OCCURENCE Rating after corrective action. New DETECTION Rating after corrective action. Resulting new RPN after corrective action.
Introduction to Process Capability
About this Module • Process capability enables the prediction of the ability of any process to produce products and services that meet their desired specifications. • This module focuses on typical manufacturing processes. Transactional and other manufacturing processes are not discussed here. • The principles of process capability will be introduced and Minitab will be used to calculate process capabilities.
Learning Objectives At the conclusion of this module participants will be able to:
1.Recognize the value of and uses for process capability. 2.Calculate and explain the capability of processes whose output is normally distributed. 3.Predict the probability that the output of a process will be within its specification limits.
We Live in a Statistical World Basic Statistics
• Statistics have a pervasive influence on our lives – Every day there is another poll – Sampling is being used to perform many aspects of the census – All major economic indicators are based on samples – TV ratings are based on samples – Statistics determine insurance rates
• Quantum physics has demonstrated that probability determines the structure and
Types of Statistics Definitions Descriptive statistics is the process of describing the information we have. We summarize information from a sample or population give a clear understanding, or description, of the data. Inferential statistics is the process of using information from a smaller set of data (sample) to reach conclusions or inferences about a larger group (population). Usually, we have only sample information, not the entire population, and must infer understanding of the population based on our sample. We want these conclusions to be mathematically correct.
Data Types Definitions Attribute Yes - no Good - bad Accept - reject Discrete Multiples of whole units Can not be meaningfully divided Count or classification Continuous Can be meaningfully divided into finer and finer increments of precision weight, length, voltage, time
Measures of Central Tendency - Location Definitions Mean - the sum of all members divided by the population size (average) j
µ = Population mean= X = Sample mean
∑ X , X , X ... X 1
1
2
3
j
N
Mode - the most frequently occurring or most likely value Median - the fiftieth percentile (half the values are above and half below the median)
Population Versus Sample Definitions Population Size N n Location Average (Mean) µ Dispersion: Variation Variance σ Std dev σ Range
2
Samples x
s2 s R = XHi -XLo
Statistics infer information about the parameters of the population.
Quantifying Dispersion - Spread Definitions x1
X
xn x2
We could add the differences between each value x and the average of the values x however that would always yield zero. Therefore we square the difference between each x and x, to eliminate the negatives and emphasize the2 outliers, then take the average of the results. σThis is defined as the variance or σ 2. Obviously, σ =
Attributes of the Histogram - Location & Spread Definitions
n
Number of Cases = 50 Mean & Median = 75 Standard Deviation = 8.3299 Range = 40 Variance = 69.388 Minimum = 55 Maximum = 95
14 12
F r 10 e q 8 u e 6 n c 4 y
i=1
n− 1
n
X i X=µ ˆ=∑ i=1 n Variable X measurements:
2
0 50
s=σ ˆ=
2 ( X − X ) ∑ i
60
70
80
90
Values of X
100
110
75 85 60 80 70 80 65 75 70 75
80 70 80 75 75 55 70 85 75 95
75 70 80 75 75 70 80 90 75 90
65 85 80 70 75 70 75 80 80 60
70 70 65 85 85 85 65 65 80 65
Measures of Variability - Variance = Sigma Squared Definitions uSigma
Squared is a measure of dispersion of the population about the mean uVariances are not in the units of interest; standard deviations are in the units of interest uVariances are additive; standard deviations are not additive...
…so σ
2
1
but, σ
+σ
1
+σ
2
+ σ
3
2
+ σ
3
2
2
is OK,
is NOT OK
Measures of Variability – S. D. = Sigma Definitions Standard Deviation is a measure of dispersion of the population about the mean σ = the units of interest and is population standard deviation µ = population mean N = total population s = estimate of standard deviation 2 2 2 µ − + − + − µ n = sample size X1 µ X2 X3 ... X N −µ σ (X )= N
(
σˆ = s =
(X
) (
1
−X
) + (X
) (
2
2
−X
) + (X
) (
2
n-1
3
−X
) ...(X 2
n
−X
)
2
)
2
Normal Distribution Each curve shown here has: u An area of one u A mean of zero u A standard deviation of σ
Therefore, the same % of the population is under each of the curves for n σ about the mean.
Quantifying the Normal Distribution Definitions
µ −3σ µ +3σ
µ −2σ
µ −1σ 68.26% 95.46% 99.73%
µ
µ +1σ
µ +2σ
Probability Density Function – Standard Normal Distribution Definitions Area under the curve = 1 σ =1 µ =0 Any normal distribution can be converted to a standard normal distribution
The formula for the probability density function is − z2
1 f ( z) = e 2π
2
The Standard Normal Transform Definitions
X −µ Z= σ Permits conversion of any data point (X) into a Z value. This value allows us to look up the percentage of the population that is above and below the data point.
Sample Questions………
Q.
A new iron ore mine is discovered. 10 Kg ore is collected from each of 20 spots.
1.
b. This procedure is called as __________ . c. Average is calculated from iron content of each of 20
spots. This value is called as ________________ d. If we calculate average, range and standard deviation from the iron content values of each lot, this data is called as ________________ . e. Predictions are made regarding average iron content of the mine, total iron that can be extracted, impurities present etc. the analysis is called as ___________ . f. The above calculations will give answers which will be100% correct. True / False
Answers a.The procedure is called as SAMPLING. b. c.The value is called as STATISTIC. d. e.The values are called as STATISTICS. f. g.The analysis is called as STATISTICAL ANALYSIS. h. i.The Statement is FALSE.
Basic Principle • All measures of process capability are based on the concept of calculating the number of standard deviations between the process center and the specification limits. • A Six Sigma process has six units of standard deviation between the process center and both specification limits.
LSL
USL
Visualizing Process Capability
Process width Specification width
Quantifying Process Capability If we assume the process is centered on the target and does not shift or drift the yields would be.
Yield of a one sigma process 0.683
LS L
US L
Process Sigma
Yield
1 2 3 4 5 6
0.6826895 0.9544997 0.9973002 0.9999367 0.9999994 1
The Standard Deviation 1 Sigma - 68% 2 Sigma - 95% 3 Sigma - 99.73 %
µ
σ =
1σ Upper Specification Limit (USL) Target Specification (T) Lower Specification Limit (LSL) Mean of the distribution (µ ) Standard Deviation of the distribution (σ )
Σ (X – X)2 n
p(d)
T
USL
3σ
Calculating Yield We know that Z is the number of units of standard deviation on a standard normal curve which has a mean of zero and a standard deviation of one. We also know any normal distribution can be converted to the standard normal using the Z equation.
x −µ Z = σ
X −X Z = σˆ
If the specification limits are substituted for x we can determine the number of units of standard deviation between the process center and the specification limits on the standard normal curve. Then we can use the tables to look up the probability a value will be less than that number.
In most cases we do not know µ or σ so we substitute the sample statistics for the population parameters as shown.
Calculating Yield The mean time taken for completing an operation is 500 hrs.
and this is normally distributed with a standard deviation of 100 hrs. 1. What is the probability that an operator taken at random will take between 500 to 650 hrs to complete the operation? 2. What is the probability that he will take > 700 hrs?
Express in graphical form also.
Calculating Yield – Example 1. What is the probability that an operator taken at random will take between 500 to 650 hrs to complete the operation?
Z =
x −µ σ
= (650 – 500) / 100 = 1.5
Looking up z table, the corresponding value under the
Standard Normal Distribution is 0.4332. i.e. 43%.
Calculating Yield – Example 2. What is the probability that he will take > 700 hrs? 3.
x − µ= (700 – 500) / 100 = 2 σ Looking up z table, the corresponding value under the
Z =
Standard Normal Distribution is 0.4772.
Thus the probability of an operator taking more than 700 hrs
is (0.5 – 0.4772) = 0.0228, i.e. slightly over 2%.
Calculating Yield Example Consider a process that has the following specification limits: Lower Specification Limit (LSL) of -1 and a Upper Specification Limit of 1. Data indicates the process is centered on 0 with a standard deviation of 1. What is the yield? Using tables or software to look up the area under the curve when Z=1 we USL-X ZUSL= find .8413. This means that 84.13% of ˆ σ the product has a value less than the 1-0 upper specification limit. ZUSL= =1 1 Again using tables or software to look LSL-X ZLSL= ˆ σ -1-0 ZLSL= = −1 1
up the area under the curve when Z=-1 we find .1586. This means that 15.86% of the product has a value less than the lower specification limit.
What if the Process Shifts? Generally speaking, processes have been observed to shift and/or drift 1.5 standard deviations over time. How would that effect the yield of a one sigma process?
LSL
-4
-3
-2
-1
USL
0
1
Calculating Shifted Process Yield Using tables or software to look up the USL-X ZUSL= area under the curve when Z=-.5 we ˆ σ find .3085 1-0-1.5 ZUSL= = −.5 1 LSL-X Again using tables or software to look ZLSL = ˆ σ up the area under the curve when Z=2.5 we find .0062. -1-0-1.5 ZLSL = = −2.5 1 Subtracting the two we obtain .3023
Using These Principles • Process capability and process capability indices are unambiguous and will be addressed first. • Process sigma is somewhat ambiguous and will be addressed second.
Process Capability Terms Measures of the ability of a process to produce compliant products/services: Cp - Short-term process capability uFor
a limited period of time (not including shifts and drifts)
uDoes uAlso
not consider process centering
known as process entitlement
Cpk - Short-term process capability index uFor
a limited period of time (not including shifts and drifts)
uDoes
consider process centering
Pp - Long-term process capability uFor
an extended period of time (including shifts and drifts)
uDoes
not consider process centering
Ppk - Long-term process capability index uFor
an extended period of time (including shifts and drifts) See formulae on next page. uDoes consider process centering
Capability Formulae USL-LSL Specification Width (s) Cp = Short-Term Process Width = µ ST 6σ
Pp = Cpk = Ppk =
Specification Width (s) = Long-Term Process Width Lesser of: Lesser of:
USL-X µ ST 3σ
or
USL-X µ LT 3σ
or
USL-LSL µ LT 6σ X-LSL µ 3σ ST
X-LSL µ 3σ LT
Using Minitab The data is continuous so test for normality Stat>Basic Statistics>Normality Test
The Normality Test Probability Plot of Caps Normal 99.99 99
Percent
95
Mean 1.000 StDev 0.001986 N 750 AD 0.619 P-Value 0.107
80 50 20 5 1 0.01 0.992 0.994 0.996 0.998 1.000 1.002 1.004 1.006 1.008 Caps
Worksheet: Bottle Caps.MTW
The P value is > .05 therefore do not reject the assumption of normality.
Using Minitab to Calculate Process Capability
Minitab Results Process Capability of Caps LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within Overall Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
2.26 2.55 2.48 0.83 0.84
5 0 5 0 5 0 5 0 94 996 997 999 000 002 003 005 9 0. 0. 0. 0. 1. 1. 1. 1. Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
Worksheet: Bottle Caps.MTW
Let’s examine this in detail
Process Data Process Capability of Caps LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within
ly from the data. The within standard deviation Overall is the pooled standard Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
2.26 2.55 2.48 0.83 0.84
Observed Performance Process Capability of Caps
ent of product that was outside of the upper and lower specification lim Within LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Overall Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
2.26 2.55 2.48 0.83 0.84
Expected Within Performance Process Capability of Caps
utside of the upper and lower specification limits on an short term basis. Thi LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within Overall Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
2.26 2.55 2.48 0.83 0.84
Expected Overall Performance
ower specification limits on an long term basis. This projection is based on t Process Capability of Caps
LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within Overall Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
2.26 2.55 2.48 0.83 0.84
Potential Within Capability Process Capability of Caps
rocess mean, the respective specification limits and the within standa ted within yield (.982) left hand tail of a standard normal then looking Within LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Overall Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83
or Z LSL .
Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
2.26 2.55 2.48 0.83 0.84
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
Note: Minitab uses within to describe short term variation and overall to describe long term variation.
Overall Capability
Process Capability of Caps process mean, the respective specification limits and the overall stand cted within yield (.981) left hand tail of a standard normal then looking Within LSL
USL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Overall
or Z LSL .
Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
5 0 5 0 5 0 5 0 94 996 997 999 000 002 003 005 9 0. 0. 0. 0. 1. 1. 1. 1. Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
2.26 2.55 2.48 0.83 0.84
Within - Between Process Capability of Caps LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within Overall
e as indicated by the Within and Between lines being very close Potential (Within) Capability Z.Bench 2.26 Z.LSL 2.55 Z.USL 2.49 Cpk 0.83 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
5 0 5 0 5 0 5 0 94 996 997 999 000 002 003 005 9 0. 0. 0. 0. 1. 1. 1. 1. Observed Performance % < LSL 0.40 % > USL 0.67 % Total 1.07
Exp. Within Performance % < LSL 0.54 % > USL 0.64 % Total 1.18
Worksheet: Bottle Caps.MTW
Exp. Overall Performance % < LSL 0.54 % > USL 0.65 % Total 1.19
2.26 2.55 2.48 0.83 0.84
Calculating Cpk and Ppk
Calculating Cpk and Ppk
e process mean, the respective specification limits and the within standard d Process Capability of Caps cted within yield (.982) left hand tail of a standard normal then looking up the LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within Overall
of CPL or CPU.
Potential (Within) Capability Cp 0.84 CPL 0.85 CPU 0.83 Cpk 0.83 Overall Capability Pp PPL PPU Ppk Cpm
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance PPM < LSL 4000.00 PPM > USL 6666.67 PPM Total 10666.67
Exp. Within Performance PPM < LSL 5355.08 PPM > USL 6432.04 PPM Total 11787.12
Worksheet: Bottle Caps.MTW
Exp. Overall Performance PPM < LSL 5395.59 PPM > USL 6478.48 PPM Total 11874.07
0.84 0.85 0.83 0.83 0.84
Calculating Cpk and Ppk Process Capability of Caps
e process mean, the respective specification limits and the overall standard d cted within yield (.9813) left hand tail of a standard normal then looking up the LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 1.00006 Sample N 750 StDev(Within) 0.00198431 StDev(Overall) 0.00198636
Within Overall
of PPL or PPU.
Potential (Within) Capability Cp 0.84 CPL 0.85 CPU 0.83 Cpk 0.83 Overall Capability Pp PPL PPU Ppk Cpm
45 60 75 90 05 20 35 50 99 .99 .99 .99 .00 .00 .00 .00 . 0 0 0 0 1 1 1 1 Observed Performance PPM < LSL 4000.00 PPM > USL 6666.67 PPM Total 10666.67
Exp. Within Performance PPM < LSL 5355.08 PPM > USL 6432.04 PPM Total 11787.12
Worksheet: Bottle Caps.MTW
Exp. Overall Performance PPM < LSL 5395.59 PPM > USL 6478.48 PPM Total 11874.07
0.84 0.85 0.83 0.83 0.84
A Process that Drifts Consider a similar process that does change over time. The data is in Caps Drift.MTW. First test for normality
Normality Test Probability Plot of Caps Drift Normal 99.99
Mean 1.000 StDev 0.001291 N 720 AD 0.326 P-Value 0.520
99
Percent
95 80 50 20 5 1 0.01 0.9950
0.9975
Worksheet: Caps Drift.MTW
1.0000 Caps Drift
1.0025
1.0050
Do not reject the assumption of normality.
Capability Analysis
Capability Analysis Process Capability of Caps Drift
time as indicated by the difference between the WithinWithin and
hart.
LSL
Target
USL
Process Data LSL 0.995 Target 1 USL 1.005 Sample Mean 0.999998 Sample N 720 StDev(Within) 0.00102066 StDev(Overall) 0.00129055
Overall Potential (Within) Z.Bench Z.LSL Z.USL Cpk
Capability 4.76 4.90 4.90 1.63
Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
0.9960 0.9975 0.9990 1.0005 1.0020 1.0035 1.0050 Observed Performance % < LSL 0.00 % > USL 0.00 % Total 0.00
Exp. Within Performance % < LSL 0.00 % > USL 0.00 % Total 0.00
Worksheet: Caps Drift.MTW
Exp. Overall Performance % < LSL 0.01 % > USL 0.01 % Total 0.01
3.70 3.87 3.88 1.29 1.29
Process Capability Exercise 1
1 ± .06 Inches
Data indicate the process is centered with a standard deviation of .02. Calculate the yield.
Exercise 1 Visualizing the Answer -.06
-.04
-.02
+.02
+.04
+.06
Process average
Design width (.12 Inches)
There are 3 units of standard deviation between the process average and the specification limits therefore this is a 3 sigma process (short term).
Exercise 1 Calculating the Yield Using tables or software to look up the USL-X ZUSL= area under the curve when Z=3 we ˆ σ find .9986 1.06-1 ZUSL= =3 .02 Again using tables or software to look LSL-X ZLSL = up the area under the curve when Z=-3 ˆ σ we find .00135. .94-1 ZLSL = = −3 Subtracting the two we find a yield of . .02 9973
Exercise 2 Assume a process owner has asked you to analyze the data in Process Capability Exercise 1.MTW. Parts A and B are made on different machines in lots (subgroups) of 5. The customer has established specification limits of 10 ± .1 and requires a Ppk of 1.33. Prepare a brief presentation to describe your analysis and recommendations? Remember to present data practically, graphically and analytically.
Exercise 2 Normality Tests Probability Plot of Part A Normal 99.99
Mean 10.00 StDev 0.05049 N 750 AD 0.420 P-Value 0.324
99
Percent
95 80 50 20 5 1 0.01
9.8
9.9
10.0 Part A
10.1
10.2
Worksheet: Process Capability Exercise 1.MTW
Probability Plot of Part B Normal 99.99
Mean 10.00 StDev 0.05647 N 750 AD 0.248 P-Value 0.752
99
No reason to reject the assumption of normality for either part.
Percent
95 80 50 20 5 1 0.01
9.8
9.9
10.0 Part B
10.1
Worksheet: Process Capability Exercise 1.MTW
10.2
Exercise 2 Process Capabilities
Exercise 2 Part A Process Capability Process Capability of Part A LSL
Target
USL
Process Data LSL 9.9 Target 10 USL 10.1 Sample Mean 10.0009 Sample N 750 StDev(Within) 0.0496334 StDev(Overall) 0.0504922
Within Overall Potential (Within) Capability Cp 0.67 CPL 0.68 CPU 0.67 Cpk 0.67 Overall Capability Pp PPL PPU Ppk Cpm
9.88 9.92 Observed Performance % < LSL 1.87 % > USL 2.80 % Total 4.67
Exp. Within Performance % < LSL 2.10 % > USL 2.30 % Total 4.40
9.96 10.00 10.04 10.08 10.12 Exp. Overall Performance % < LSL 2.28 % > USL 2.49 % Total 4.77
Worksheet: Process Capability Exercise 1.MTW
0.66 0.67 0.65 0.65 0.66
Exercise 2 Prepare the Control Charts
Control Chart Shows Process Stability Xbar-R Chart of Part A UCL=10.0675 Sample Mean
10.05
__ X=10.0009
10.00
9.95 LCL=9.9343 1
16
31
46
61
76 Sample
91
106
121
136
Sample Range
UCL=0.2441 0.2
4 0.1
_ R=0.1154
44 4
0.0
LCL=0 1
16
31
46
61
76 Sample
91
Worksheet: Process Capability Exercise 1.MTW
106
121
136
Process Capability Part B Process Capability of Part B LSL
Target
USL
Process Data LSL 9.9 Target 10 USL 10.1 Sample Mean 9.99961 Sample N 750 StDev(Within) 0.0496334 StDev(Overall) 0.0564727
Within Overall Potential (Within) Capability Z.Bench 1.71 Z.LSL 2.01 Z.USL 2.02 Cpk 0.67 Overall Capability Z.Bench Z.LSL Z.USL Ppk Cpm
9.84 Observed Performance % < LSL 4.13 % > USL 4.00 % Total 8.13
9.90
Exp. Within Performance % < LSL 2.24 % > USL 2.16 % Total 4.39
9.96
10.02 10.08 10.14
Exp. Overall Performance % < LSL 3.89 % > USL 3.77 % Total 7.66
Worksheet: Process Capability Exercise 1.MTW
1.43 1.76 1.78 0.59 0.59
Control Chart Shows Time Based Variation Xbar-R Chart of Part B 1 1
11
1
1
1 5
Sample Mean
10.05
UCL=10.0662
__ X=9.9996
10.00 9.95
1
9.90 1
5 1
5 1
1 16
31
46
61
76 Sample
91
106
LCL=9.9330
1 121
136
Sample Range
UCL=0.2441 0.2
4 0.1
_ R=0.1154
44 4
0.0
LCL=0 1
16
31
46
61
76 Sample
91
Worksheet: Process Capability Exercise 1.MTW
106
121
136
Confidence Intervals
About This Module… Confidence Intervals (CI) permit us to state that we are X% confident that the population parameter of interest is at most a specified interval from the sample statistic.
Six Sigma, A Quest for Process Perfection Meet Goals and Attack Variation
\DataFile\PurchOrd.mtw \DataFile\PwrSuply.mtw \DataFile\Conf-Int.mtw \DataFile\OEack.mtw
What We Will Learn...
1.Significance of confidence intervals 2. 3.How to calculate confidence intervals for: –Means –Standard deviations or Variation
Confidence in the Midst of Uncertainty? and Standard Deviation statistics are: –estimates of the population Mu’s (µ ) and Sigma’s (σ ) –based on one sample
Ninety-five Percent Certain
uMean
Ø uVariability exists from sample to sample u uBy
using statistically based confidence intervals, uncertainty can be quantified
u u Usually, 95%are confidence intervals The chances approximately 95
are out of 100 calculated that the calculated confidence interval contains the population parameter, or… With 95% certainty, the population parameter is inside the confidence interval.
Population vs. Sample Population is the entire area of interest. Sample is a subset of the population. What is the relationship between the population and the sample?
Population
Sample
How representative is this sample?
Confidence Interval Symbols and Definitions Measure Mean
Population Sample Parameter Statistic
µ
X
Use Z n ≥ 30 σ is known t n < 30
Variance
σ2
s2
χ
2
Standard Deviation
σ
s
χ
2
Process Capability
Cp
Cp
^
χ
2
p
^ p
Proportion Alpha Risk
α
F or Z (approx) Typically .05
Confidence Intervals (CI) CI take the general form : C.I.=Statistic +/- K * (Standard Deviation) Statistic= Mean, Variance, CP, etc. K = Constant based on a statistical distribution CI reflect the sample to sample variation of our point estimates We will look at CI for: µ , σ
X
, and C P
What is the Student t-distribution? The Student t distribution is a family of bell shaped (Normal like) distributions that vary by degrees of freedom (sample size) - the fewer degrees of freedom, the wider and flatter the distribution. 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05
DF2
DF10
DF30
4
5 3.
3
5 2.
2
5 1.
1
5 0.
0
5 -0 .
-1
5 -1 .
-2
5 -2 .
-3
5 -3 .
-4
0
t-Distributions, Normal Approximation, Risk To give an idea of the values of t compared to Z for 95% (α = 0.05), look at the table below: Sample 5 10 20 30 100 1000
t-value 2.78 2.26 2.09 2.05 1.98 1.96
Z-value 1.96 1.96 1.96 1.96 1.96 1.96
α = risk α /2=0.025
We can use Z to estimate t if n ≥ 30 and σ is known STATISTICS FOR EXPERIMENTERS-- BHH
t
α /2= 0.025
Hypothesis Testing
About This Module… Hypothesis Testing helps: uDetermine if there is a statistically significant difference between two relatively small samples uQuantify the risks of making an incorrect decision
Six Sigma, A Quest for Process Perfection Meet Goals and Attack Variation
What We Will Learn 1.How to test variable data a.Use a t-test to compare two means b.Alpha (α ) and Beta (β ) Risks c.Use a paired t-test to compare paired treatments d.Use test for equal variances 2.How to test discrete data a.Compare proportions b.Compare discrete data Ø
Real World Scenario Design: Determine if two alternate design changes are significantly different. Manufacturing: Determine if two different types of material wear differently. Administrative/Transactional / Service: Determine if the change to a process affected the cycle time.
Purposes of Hypothesis Testing uDetermine
if there is a real difference between ? and ? .
uUse
relatively small samples to answer questions about the population.
uQuantify
the associated risks.
Example Old Design uHard disk transfer speed 89.7 (megabytes per second) is 81.4 marginal. A new design is 84.8 proposed. 87.3 79.7 uAn Engineering Change 85.1 Notice (ECN) is incorporated 81.7 83.7 uIs the new design better? 84.5
New Design 84.7 86.1 91.9 86.3 79.3 86.2 89.1 83.7 88.5
To answer this, we need some fundamentals of significance testing first!
Steps in Hypothesis Testing 1.Define the problem 2.Determine the objectives 3.Establish the Hypothesis –Write the Null Hypothesis (H0) –Write the Alternative Hypothesis (Ha) 4.Determine the appropriate statistical test (assume distribution Z, t, F) 5.State the alpha risk (usually 5 %) 6.State the beta risk (usually 10-20 %) 7.Establish the effect size (delta) 8.Compute the sample size 9.Develop a sampling plan
10.Select the samples 11.Conduct the test and collect data 12.Calculate the test statistic (Z, t, or F) from the data 13.Determine the probability that the calculated test statistic has occurred by chance 14.If that probability is less than alpha, reject H0 15.If that probability is greater than alpha, do not reject H0 16.Translate the statistical conclusion into a practical solution
Significance Tests uUsed
to assess evidence provided by sample data to reject, or fail to reject a claim about a population parameter.
uNull
hypothesis (Ho) is the statement we assess.
uHo
is usually stated as, “there is no difference”.
uAlternate
hypothesis (Ha) is usually stated as “there is a difference”.
uWe
fail to reject Ho unless there is convincing evidence to reject it.
Typical Examples
Ho :µ a = µ b Ha :µ a ≠ µ b Ho :σ a = σ b Ha :σ a ≠ σ b Ho : pa = pb Ha : pa ≠ pb
What does 5% Level of Significance Mean? This means that we will reject the null hypothesis if the difference between the sample statistic and the hypothesized population parameter is so large that it would occur, on an average, only 5 or fewer times in every 100 samples when the hypothesized population parameter is correct.
Type I and II Errors: Associated Risks Type I errors are made when we reject the null hypothesis when in fact it is true. Alpha (α ) risk is the probability of making a type I error.
This risk is typically set at 5%.
Type II errors are made when we fail to reject the null hypothesis when in fact it is false. Beta (β ) risk is the probability of making a type II error.
This risk is typically set at 10%
Risks are set before the test or experiment is conducted
The Risk Truth Table α is the risk of finding a difference when there really isn’t one. β is the risk of not finding a difference when there really is one. Action State of Nature Ho should not be rejected (Ho is true) Ho should be rejected (Ho is false)
Ho not rejected
Ho rejected
Correct Decision
Type I or producer’s risk α = P(Type I)
Type II or consumer’s risk β = P(Type II)
Correct Decision
Another Look at Risks Remember: α is the risk of finding a difference when there really isn’t one. β is the risk of not finding a difference when there really is one. Ho Ha
β α Now we can determine if the ECN improved performance
Normal Distribution and t Distribution When Population When Population SD is Known SD is Not Known Sample size n is > Normal Normal 30 distribution, z table tdistribution, Sample size < 30, Normal distribution,z ttable and we can assume distribution, z table table population is approx normal
P Value P value is the smallest level of significance that would lead to rejection of the null hypothesis Ho. eg. supposing Ho were true, what is the probability of getting a value of x-bar this far from the population mean? This probability is called a prob value or p-value.
Manual Test Null Hypothesis µ
1
†µ
2
s12 s22 Difference Upper bound = X1 − X 2 + tα ,df * + n1 n2 Difference Upper bound = -1.99 + ( 1.7459* 1.57) Difference Upper bound = .756 The upper bound for the difference in the means indicates the difference between the means of these populations could be as great as .756 (at the 95% confidence level). Therefore, the evidence is not statistically significant to conclude that the difference between the new design and the old design is less than 0. Fail to reject Ho.
Manual Test Null Hypothesis µ
t(α ,df ) =
X1 − X 2 2 1
2 2
s s + n1 n2
1
†µ
= -1.26
P = .112 P> .05 therefore fail to reject Ho.
2
Hypothesis Testing Decision Tree Ho: P1=P2 Ha: P1 P2 Minitab: Stat-Basic Stat-1or 2 proportions
Hypothesis Testing
Proportions Testing (2 factors only) Continuous Data (One factor only)
Non-normal
Attribute Data
Normal
Normality test Ho: Data is Normal Ha: Data is NOT Normal Minitab: Stat-Basic Stat-Normality Test Use Anderson-Darling
2 or more samples Ho:σ 1=σ 2=σ 3… Ha: At least 1 is different Levene’s Testfor Equal Variances Minitab: Stat-ANOVA-Test For only 2 s, this is similar to an F-test: F=(S1)2/(S2)2 If Fcalc>Fcrit , reject null (Use Chi-Squared for 1 sample)
Ho: M1 = Target Ha: M1 Target Minitab: Stat-Nonparametric-1 Sample - sign (or) 1 Sample Stat-Nonparametric-1 Sample Wilcoxon (Also used for paired comparisons Ho: M1-M2=0) M1=Median or sample 1 M target = Target Median
Ho: M1=M2=M3… Ha: At least2 2or are different More Samples Minitab: Stat-Nonparametric-Mann-Whitney (or) Stat-Nonparametric-Kruskal-Wallis (or) Stat-Nonparametric-Freidmans M1=Median sample 1, etc.
Ho: 2 factors are independent Ha: 2 factors are dependent Minitab: Stat-tables-Chi square test
Contingency Table
1 Sample
2 or More Samples
Bartlett’s Test/F-Test
Chi-Square Ho: σ 1=σ Target Ha: σ 1 σ Target Minitab: Stat-Basic Stat-Graphical Summary If σ target falls within C1: then fail to reject Ho
1 Sample T Test Ho: µ 1=µ Target Ha: µ 1 µ Target Minitab: Stat-Basic Stat-1 Sample-T (Also used for paired comparisons:Ho: µ 1=µ 2=0)
Ho:σ 1=σ 2=σ 3… Ha: σ 1 At least 2 are different Minitab: Stat-ANOVA-Test for Equal Variances For only 2 σ s, this is same as F-test: Stat>BasicStat>2 Variances F=(S1)2/(S2)2 If Fcalc>Fcrit , reject Ho
1 Sample Z Test Ho: µ 1=µ Target Ha: µ 1 µ Target Minitab: Stat-Basic Stat-1 Sample-Z (Also used for paired comparisons: Ho:µ 1=µ 2=0) Sample Size >=30 σ is known
2 Sample T Test Ho: µ 1=µ 2 Ha: µ 1 µ 2 Minitab: Stat-Basic Stat-2 Sample-T (Compares Means using pooled Std Dev) Check box to assume equal variances or Check box to assume unequal variances
One Way ANOVA
Ho: µ 1=µ 2=µ 3=… Ha: µ 1 at least 2 are different Minitab: Stat-ANOVA-One Way (Caution Bartlett’s pbasic stat>correlation Correlation of Station 1 and Station 2 = 0.959, P-Value = 0.000 The two are highly correlated (.959)
?
Is this reasonable? Are you comfortable with .959? What does it mean to you? How does the data actually look? How would you find out?
Plot the Data Graph>ScatterPlots
The Data Scatterplot of Station 1 vs Station 2 9.4 9.3 9.2 Station 1
If all of the 9.1 data points were on the9.0diagonal line, would8.9we have perfect correlation? 8.8 8.7 8.6 8.5 8.6
8.8
Worksheet: Correlat.MTW
Let’s try regression
9.0
9.2 Station 2
9.4
9.6
Regression
Fitted line plot is used when there is only one predictor.
Example 1 (cont.) Fitted Line Plot Station 1 = 1.020 + 0.8729 Station 2 9.5
S R-Sq R-Sq(adj)
9.4
0.0557288 92.0% 91.5%
9.3 Station 1
9.2
In what ways is this graph different from the preceding one?
9.1 9.0 8.9
What are the implications?
8.8 8.7 8.6 8.6
8.8
9.0 9.2 Station 2
9.4
9.6
Worksheet: Correlat.MTW
Slide 225 was actual line – this is a fitted line. Can be used for prediction.
What action would you take?
Best Fit Line Fitted Line Plot Cases = 22.47 + 0.7546 Test Piece 100
S R-Sq R-Sq(adj)
90
Cases
80 70 60
11.5131 49.4% 47.7%
By minimizing the residual sum of squares, we get a best fit line of the form:
50 40 40
50
60
70 Test Piece
80
90
100
Yi = a + bX i
Worksheet: cases.MTW
a = coefficient of the constant term or intercept b = coefficient of the predictor, X
Statistical Process Control
About This Module… Control charts portray process performance and separate causes of variation: •Random •Assignable • Control Chart Systems are: •A proven technique for improving productivity •Effective in defect prevention •Prevent unnecessary process adjustments •Provide diagnostic information •Provide information about process capability
Six Sigma, A Quest for Process Perfection Meet Goals and Attack Variation \DataFile\Attribut mtw \DataFile\Variable.mtw
What We Will Learn.
1. Control charts are a powerful tool to hold the gains. 2. How control charts discriminate between common cause and assignable cause variation. 3. Why control charts must be designed to fit the data type and the control purpose.
Process Variation Process variation is the result of: • Common causes. • Special (assignable) causes.
Common Causes • Result in normal process variation. • Are specific to each process. • Can be reduced by changing the process.
Special (Assignable) Causes • Are attributed to something outside of the process. • Result in abnormal process variation. • Do not result in process improvement if eliminated.
Uses of Control Charts 1) Attain a state of statistical control: •All subgroup averages and ranges within control limits - no assignable causes of variation present 2) Monitor a process 3) Determine process capability • Juran’s Quality Control Handbook, 4th edition, page 24.7
What happens after an out-of-control situation occurs at the core of a successful SPC program?
General Concepts w = some characteristic of interest
XW
= mean of each sample
Sw = standard deviation of w Upper Control Limit UCL = X + 3S w Centerline =
X
Lower Control Limit
LCL = X − 3Sw
Therefore 99.73% of points will be within the control limits unless there is an assignable cause
Control Chart Selection Tree Type of data
Variable
Discrete
Count
Fixed
C Chart
Fixed or variable opportunity?
Count or Classification
Variable
U Chart
Attribute
Fixed
NP Chart
No
Fixed or variable opportunity?
Variable
P Chart
IMR Chart
Subgroup >1?
Yes
X Bar and R or X Bar and S
Supplement with EWMA if CTQ is sensitive to small process shifts
X and R Control Chart Formulae & Constants X Control Limits =X ± A 2R R Upper Control Limit = D R 4 R Lower Control Limit = D R 3 Sample Size 2 3 4 5 6 7 8 9 10
A2
D3
D4
d2
1.880 1.023 .729 .577 .483 .419 .373 .337 .308
.076 .136 .184 .223
3.267 2.574 2.282 2.114 2.004 1.924 1.864 1.816 1.777
1.128 1.693 2.059 2.326 2.534 2.704 2.847 2.970 3.078
Creating Control Charts for Variables \DataFile\Variable.mtw
Creating an X-bar and R Chart
An X-Bar and R Chart Xbar-R Chart of measure1, ..., measure5 1 1
1
5
Sample Mean
41
__ X=40.000
40 6
39 1
6 1
1
38
LCL=38.706
1
5
10
15
20
25 Sample
30
35
40
45
UCL=4.743
4.5 Sample Range
UCL=41.294
3.0
_ R=2.243
1.5
0.0
LCL=0 5
10
15
20
25 Sample
30
35
40
45
Worksheet: Variable.MTW
The numbers show violations of the assumption of control. The nature of the violation is given in the session window.
X-Bar and R Chart Session Window Test Results for Xbar Chart of measure1, ..., measure5 TEST 1. One point more than 3.00 standard deviations from center line. Test Failed at points:
7, 10, 13, 16, 17, 29, 46
TEST 5. 2 out of 3 points more than 2 standard deviations from center line (on one side of CL). Test Failed at points:
10, 17, 47
TEST 6. 4 out of 5 points more than 1 standard deviation from center line (on one side of CL). Test Failed at points:
7, 32, 34
* WARNING * If graph is updated with new data, the results above may no * longer be correct.
StatGuide Interprets the Tests
Comparing the Suppliers __ X=39.894
40 39 1
4
LCL=38.580 6
8
10
12 14 Sample
16
18
20
22
_ R=2.278
2 0
LCL=0 6
8
10
12
14
16
18
20
22
24
1
1
1 5
5
6
38 4
6
1
8
10
12 14 Sample
1
16
18
20
22
UCL=41.384 _ X=40.106 LCL=38.829
5
1
24
UCL=4.683 4 _ R=2.214
2 0
LCL=0 2
4
6
8
Sample Worksheet: Variable.MTW(Supplier = 1)
5
40
2
UCL=4.816
4
42
24
4
2
Sample Mean
UCL=41.207
41
2
Sample Range
Xbar-R Chart of measure1, ..., measure5
Sample Range
Sample Mean
Xbar-R Chart of measure1, ..., measure5
10
12
14
16
18
20
Sample Worksheet: Variable.MTW(Supplier = 2)
Supplier 2’s process is less stable than Supplier 1’s process.
22
24
Add Dates to Control Charts
Adding dates to the control charts may help identify potential sources of shifts.
Adding Dates Indicates When the Shift Occurred Xbar-R Chart of Stacked Data 1s 12
5
Sample Mean
6 11
2
10
6 6
6
9 7/31/2006 8/4/2006 8/10/2006 8/16/2006 8/22/2006 8/28/2006 9/1/2006 Date
Sample Range
4.5
3.0
1.5
2
9/7/2006 9/13/2006 9/19
Detecting Gradual Process Drift Xbar-R Chart of Stacked Data 1s 12
UCL=11.850
5
Sample Mean
6 2
11
2
10
2
2 2
2
_ _ X=10.568
6 6
6
LCL=9.286 9 4
8
12
16
20 Sample
24
28
32
36
40
UCL=4.699
Sample Range
4.5
3.0
_ R=2.222
1.5
0.0
LCL=0 4
8
12
16
20 Sample
24
28
32
36
40
Worksheet: Variable.MTW
The tests detect the process shift but it would have been detected earlier if the control limits had been based on the first 20 data points.
Detecting Gradual Process Drift Minitab calculates control limits based on the entire data set be default. Freezing control limits detects shifts earlier than using the entire data set to calculate limits. Xbar-R Chart of Stacked Data 1s
Sample Mean
12
1
1 5
11
6
6
2
2
2 2
2 2
6
2
2
2 2
__ X=10.112
10
9
LCL=8.864 4
8
12
16
20 Sample
24
28
32
36
40
UCL=4.575
4.5 Sample Range
UCL=11.360
2
3.0 _ R=2.164 1.5
0.0
LCL=0 4
8
Worksheet: Variable.MTW
12
16
20 Sample
24
28
32
36
40
Rational Subgrouping •Usually consecutive units •Must come from a single distinct population •Within subgroup, variation should be white noise only •Between subgroups should capture variation due to black noise 1) 2) 3) 4)
Subgroup needs to represent the distinct population Establish minimum subgroup size to reflect the within variation Establish sample frequency to capture the between variation Collect data maintaining the sequential information •Never knowingly subgroup unlike things together •Minimize variation within each subgroup •Maximize opportunity for variation between subgroups •Average across noise not across signals •Treat charts in accordance with the use of the data •Establish standard sampling procedures Donald J. Wheeler has six guiding principles for subgrouping in a rational manner.
When to Increase Sample Size If the sample size is too small, assignable causes may produce real effects that are relatively small and unimportant. In this case, it may not be economical to take action. To minimize the number of these “nuisance” causes, the sample size should be increased using the following techniques: •Identify characteristics •Determine logical nature of subgroups •Identify sampling sequence •Measurement methods proven to be accurate
What We Have Learned. 1. Control charts are a powerful tool to hold the gains 2. How control charts discriminate between common cause and assignable cause variation 3. Why control charts must be designed to fit the data type and the control purpose
Lean Enterprise A Formula for Organizational Success
Agenda
1. Introduction to Lean, Wastes 2. 5S WPO & Visual Management 3. Standard Work 4. Value Stream Mapping 5. Quick changeover 6. Poka-yoke 7. Continuous Improvement 8. Kaizen Blitz 9. Starting Lean
Introduction to Lean and 7 Wastes
• Identify and Eliminate the 7 Wastes
Brief History of Lean • Craftsman to mass production • Mass production to lean production • Lean production: Ford to Toyota – Frederick Taylor – Taiichi Ohno – Shigeo Shingo – James Womack
• From shop floor to office and support functions then to service industry •
Craft Manufacturing
Late 1800’s
• ●
Car built on blocks as workers walked around
●
Built by craftsmen with pride
●
Components hand-crafted, hand-fitted
●
Excellent quality
●
Very expensive
●
Few produced
Mass Manufacturing • Assembly line - Henry Ford 1920s • ● ● ● ● ●
Low skilled labor, simplistic jobs, no pride in work Interchangeable parts Lower quality Affordably priced for the average family Billions produced – identical Model ‘T’
Lean History – Japan • Sakichi Toyoda at his textile mills (20’s–30’s) • Toyota Motor Company’s Kiichiro Toyoda and Taiichi Ohno made innovations (40’s) in assembly lines that provided efficient, customer-focused, streamlined processes with flow, variety, and short lead time— Toyota Production System (TPS); to face competition of GM and Ford after WWII when key need was flexibility. • Taiichi Ohno and Shigeo Shingo developed Lean based on TPS
Lean Manufacturing ●
Cells or flexible assembly lines
●
Broader jobs, highly skilled workers, proud of
product
●
Interchangeable parts, even more variety
●
Excellent quality mandatory
●
Costs being decreased through process
improvement
●
Global markets and competition.
What is Lean? “A business system for organizing and managing product development, operations, suppliers, and customer relations that requires less human effort, less space, less capital and less time to make products with fewer defects to precise customer desires compared with the previous system of mass production.”
Lean Lexicon, Lean Enterprise Institute, 2003
Definition Lean manufactuirng is aimed at the elimination of waste in every area of production including customer relations, product design, supplier networks and factory management. The goal of Lean Manufacturing is to incorporate less human effort, less inventory, less time to develop products, and less space to become highly responsive to customer demand, while at the same time producing top quality products in the most efficient and economical manner.
Why Call it “Lean”? • The term “lean” is used because lean uses “less”… •
üLabor üSpace üCapital investment üMaterials üTime between the customer order and the product shipment
Definition of Lean Lean has been defined in many different ways –
“A systematic approach to identifying and eliminating waste (non-value-added activities) through continuous improvement by flowing the product at the pull of the customer in pursuit of perfection.”
Definition by the MEP Lean Network
Give the customers what they want, when they want it, and do not waste anything.
Definition of Value Added Waste is any activity that does not add value to the final product for the customer. • Value-added is an activity that transforms or shapes raw material or information to meet customer requirements. • Non-value added is an activity that takes time, resources or space, but does not add to the value of the product or service itself. • Non-value-adding, but necessary – does not add value to the product or service but is required (e.g., accounting, governmental regulations, etc.).
Waste
“Anything that adds Cost to the product without adding Value”
Toyota Way – the 14 Principles by Jeffrey K. Liker 1. Base management decisions on long-term philosophy, even 2. 3. 4. 5. 6. 7. 8.
at expense of short-term financial goals. Create continuous process flow to bring problems to surface. Use pull systems to avoid overproduction. Level out workload (heijunka); work like a tortoise, not a hare. Build culture of stopping to fix problems, to get quality right first time. Standardized tasks are the foundation for continuous improvement and employee empowerment. Use visual controls so no problems are hidden. Use only reliable, thoroughly tested technology that serves people and processes.
Toyota Way - 14 Principles (cont.) 9. Grow leaders who thoroughly understand work, live philosophy,
and teach others. 10.Develop exceptional people and teams that follow company’s
philosophy. 11.Respect extended network of partners and suppliers by
challenging them and helping them improve. 12.Go and see to thoroughly understand situation (genchi
genbutsu). 13.Make decisions slowly by consensus, thoroughly considering
all options; implement decisions rapidly. 14.Become a learning organization through relentless reflection
(hansei) and continuous improvement (kaizen).
Liker Model Toyota Terms Genchi Genbutsu Problem Solving People and Partners
Respect and Teamwork
Kaizen
Process
Philosophy
Challenge
Liker Model - 4 Ps 1. Philosophy
Long-term thinking even at expense of short-term financial goals 2. Process • Eliminate waste by focusing on flow, pull, workload balance, error reduction, standardization, visual controls, and jidoka or use of reliable, tested technology/automation with mistake proofing and human touch 3. People and Partners • Respect, develop, and challenge people 4. Problem Solving • Fix and prevent problems by continual learning, going to place where problem occurs, getting hands dirty, and making good decisions based on fact •
What Is Lean? Lean is a methodology
• that allows organizations to drastically improve bottom line • by improving processes and monitoring everyday business activities to reduce errors • in ways that increase value and minimize work, nonvalue-add tasks, and waste while increasing customer satisfaction -
Based on idea that faster processes yield less waste, less cost, less work in process, less complexity, higher quality, and happier customers
Womack and Jones Model 1.Define value from customers’ perspective 2.Document value stream 3.Improve flow of value stream 4.Drive for pull versus push 5.Continuously improve
Lean Principles • Create value for customer • Understand: – Who is customer – person or entity who is recipient of product or service; one who places value on output; catalyst/trigger in value chain • Another business • Someone inside own business • Specific individual, group, or team • Consumers—ultimate customer
– What customer considers valuable • Make value flow based on customer’s needs
Lean Principles (cont.) • Consider life cycle of information, materials, processes, products, and services • Look for process problems that prevent people from performing best work • Eliminate waste
– Non-value-add steps – WIP – Cost • Standardize work • Do not become distracted by other stakeholders •
Value-Add Quiz
In which category should the following be placed? Activity Value Add Attending weekly team coordination meeting Filtering through daily e-mail list Reporting status to upper management Gaining multiple approvals on documents Gaining management approval for routine actions Expediting document through approval list Writing formal policies and procedures Writing brief work-method instructions Gaining regulatory or agency approvals Creating ISO 9000 documentation Hunting for needed information to do your job Building “best practices” database Holding lessons learned meeting Spending time on process improvements
Type 1
Type 2
Lean vs. Traditional Lean
• • • • • • • •
Simple and visual signals Demand driven Inventory as needed Reduce non-value added Small lot size Minimal lead time Quality built Value stream managers
Traditional
• • • • • • • •
Complex Forecast driven Excessive inventory Speed up value-added work Batch production Long lead time Inspected-in Functional departments
Benefits of Lean Manufacturing Helps in – • Cost reduction Lead Time Reduction • Cycle time reduction Productivity Increase • “Waste” minimization WIP Reduction • Elimination of non- Quality value-added Improvement activities Space Utilization • Resulting in a more “lean,” competitive, agile, and marketresponsive
Real Results 0
50
100
Why the Emphasis on Lean Now? • • • • • •
Global economy Pressure from customers for price reduction Fast-paced technological changes (e.g. Internet auctions) Continued focus on quality, cost, delivery Higher and higher expectations of customers Quality standards, such as QS-9000 (or TS 16949), the new ISO 9000:2000 • Holding on to “Core Competencies,”outsourcing the rest • Market-driven pricing: Customers expect better performance at lower prices year after year
Evolution of Lean Across Markets • Proven global concept since 1980s • Transformed business processes across many industries: –Automotive –Aerospace • Other industries beginning to embrace Lean concepts with excellent results: –Construction –Hospitals –Pharmaceutical Manufacturing –Service Organizations
Pricing Model Costs Increase
Old Way
Maintain Profits
Increase Price
New Way
Cost + Profit = Price Customers Demand Lower Prices
If Costs Stay the Same
Profits Decrease
Price - Cost = Profit
What can we do?
Pricing Model Old Way
Costs Increase
Maintain Profits
Increase Price
Cost + Profit = Price
New Way
Customers Demand Lower Prices
Implement Lean
Increased Profits
Price - Cost = Profit
Core Concepts of Lean • Creativity before Capital • A solution that is not-so-perfect implemented today, is better than a perfect solution that is late. “Just do it.” • Inventory is not an asset, but a waste/cost. • Typically, 95% of lead-time is not value added. • Lean implementation using the Plan-Do-CheckAct methodology • Continuous Improvement environment: both incremental and breakthrough. • Lean is a never-ending philosophy.
Aluminum Can Example •From aluminum ore to usable cans, it typically takes about 300 days Bauxite
Cryolite
Aluminum
Cast Product
3 hours Cans
Sheet
Rolled Plate
Guess what the total value-added time is?
Video • Introduction to Lean
7 Wastes of Lean
• • • • • • • •
“OMIT What U DO”
Overproduction Motion Inventory Transportation (Movement) Waiting Defects (Correction) Over-processing Underutilized People
C O M M WI P
Overproduction Making more-earlier-faster than the next process needs it
•Just in case logic •Unbalanced workload •Unleveled scheduling •False sense of efficiency
•Printing 20 copies of a report that only 3 people look at •All-staff e-mails when it pertains to only a few •Waiting to “batch” work
Motion Any movement of people that does not add any value to the product or service
•Poor layout •Inefficient Workplace Organization •Lack of Standardization, inconsistent work methods •People, Material and Machine Ineffectiveness
•Where is are copier, printer, files and coffee-maker located? •How far does the paperwork travel?
Inventory Any supply in excess of one-piece flow
•Just in case logic •Unbalanced workload •Unleveled scheduling •Unreliable suppliers •Reward system •“Pack rat” mentality
•Printed forms or tags that become obsolete •8 weeks of paper located by the copier •How many pens do you have in your desk drawer?
Transportation Moving people, materials and information around the organization
•Poor layout •Inefficient “flow” •Carrying large quantities
•Moving “banker’s boxes to a storage area •Mail carts •Messenger services
Waiting Waiting for… man, machine, materials, information etc.
•Just in case logic •Unbalanced workload •Unleveled scheduling •Unplanned downtime •Needs not understood
•Waiting for files or information •Need a signature •Customer reply to a voice-mail or email •Someone is printing 50 copies of a 70 page report
Defects
Information, products and service that need correction •Not using Jidoka or Poka-yoke •Lack of Standardization, inconsistent work methods •Ineffective communication •Little investment in training
•Have to fix paperwork that is not completely filled in or track down the right person to get the information •An entry error causes the wrong actions like shipping too many, or too few to the wrong address, etc.
Over-processing Effort that adds no value to the product or service from the customer’s standpoint
•Just in case logic •Inconsistent work methods •Ineffective communication •Redundant approvals •Excessive information, extra copies
•Multiple sign-offs or checks
Underutilized People Not utilizing people’s experience, skills, knowledge, creativity
•Not utilizing Teams •Organization structure •Poor hiring practices •Little investment in training
•Lack of suggestions •“That’s not my job” attitude •Waiting for lead from management
Mura and Muri • Mura (unevenness) – variation in operation, wasted resources when quality, cost, or delivery cannot be predicted
– Testing/inspection, Containment, Rework, Returns, Overtime, Unscheduled travel • Muri (overdoing) – unnecessary or unreasonable overburdening of people, equipment, or systems when demand exceeds capacity or tasks are not designed properly including harmful, wasteful, or unnecessary tasks
Building Blocks of Lean Continuous Improvement & Kaizen Blitz Cellular & Pull System & TPM JIT Flow Kanban Poka-yoke
Self Inspection Batch Size Reduction
POUS Layout
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
Building Blocks of Lean Continuous Improvement & Kaizen Blitz Cellular & Pull System & TPM JIT Flow Kanban Poka-yoke
Self Inspection Batch Size Reduction
POUS Layout
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
5 Words that begin with “S” Japanese Seiri Seiton
Translation Organization Neatness
Conversion Sort Set in order
Seison Seiketsu
Cleaning Shine Standardization Standardize
Sweeping Standardize
Shitsuke
Discipline
Selfdiscipline
Sustain
*Other Sorting Simplifying access
* There are several other conversions
5 Steps to Workplace Organization 1 Clear/Sort By red tagging
5 Continuous Improvement Sustain Discipline
Waste
4 Maintain/Standardize Establish standards
2 Organize/Straighten A place for everything
3 Clean/Sweep Housekeeping / Inspection
Workplace Scan
“Understand your Current State”
• Start with a workplace Scan • Team Based • Define the boundaries • Complete a Diagnostic Checklist • Draw a Spaghetti Diagram • Take “Before” Photos • Starts the 5S Program •
Workplace Scan Display Area Details
Checkli st Score
Spaghetti Diagram
Before Photos
After Photos
Sort
“When in doubt, move it out”
• Move unneeded items out of the area • Use the Red Tag Technique • Use a Temporary Red Tag Holding Area • Criteria for unneeded items – “30-day Rule”
Name____ Date___ Item _____________ Reason _________
• Keep only what you need in the area •
Set in Order
“A place for everything and
everything in its place.”
• Make it easy for anyone to find – “30-second Rule”
• Make it obvious if an item is out of place • Decide where to keep items, how many items to keep, how and when to replenish items • Make it Visual
Shine
“Clean and Inspect”
• Get items to a like-new condition – “10 Second Rule”
• Must plan Shine – assignments & supplies • Perform as a Team • Prevent dirt, grime, or contamination • Repair as needed •
Standardize
“Create the rules and follow them”
• Determine how the first 3S conditions are met • Use “One-Point Lessons” • Maintain and monitor the conditions • Use Visual techniques
Sustain
“Make 5S a habit”
• 5S is not something additional, it is part of everyone’s daily job • Supports discipline • Train • Communicate • Support from Management • Reward and recognition
5S is Fundamental to Lean • 5S is directly related to other Building Blocks – Teams – Visual – POUS – Standard Work – TPM
Point-Of-Use Storage • Raw material and WIP are stored at workstation where used, which reduces the inventory that can be carried. • Works best if vendor relationship permits frequent, on-time, small shipments (JIT). • Simplifies physical inventory tracking, storage, and handling.
Carpenter Story • Does the carpenter walk back to the toolbox every time a tool is needed? • Which waste is this? • What does the carpenter do?
Proximity • Typically, up to 60% of time is spent on finding/collecting items needed. • Minimize non-value activities • Store as close as possible and within reach • Layout and workstation design should accommodate required materials • Try to use the packaging from the supplier or have the supplier change packaging
POUS Components • Have the: – Information – Parts & materials – Tools & equipment
that you need to perform you tasks within reach
•
POUS Workplace Zones • Items used most often (i.e., daily) should be kept within reach • Items used less often (i.e., weekly) should be kept close-by • Items used rarely (i.e., monthly) should be kept in the vicinity
Daily Weekly Monthly
Location of items • Use horizontal transfers and gravity feeds when possible • Support heavy objects • Set items ergonomically • Must be comfortable for a day’s work
Benefits • Supports 5S & Visual and other Building Blocks • Simplifies inventory tracking and accuracy • Reduces waiting, inventory, motion and transportation waste
Benefits of 5S • Improved equipment reliability • Superior quality • Increased productivity • Better workflow • Enhanced Safety • Reduced inventory • More pleasant place to work • Impress customers •
Video • Introduction to 5S
Building Blocks of Lean Continuous Improvement & Kaizen Blitz Cellular & Pull System & TPM JIT Flow Kanban Poka-yoke
Self Inspection Batch Size Reduction
POUS Layout
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
Visual
Signs, lines, labels and color coding
Why Visual? • What you need to know • Cockpit view • Information sharing
How do you know where to park when you
drive to a shopping mall?
Does someone have to tell you where to
park?
How to Apply Visual • Use Signs, Lines,
Examples
Labels and Color-
• Productivity Goals
coding
• Quality Goals
• Charts, pictures, lights, scoreboards • Kanban, Andon lights • Inventory Levels
• Delivery schedules • Set-up specification • Safety Initiatives • Attendance Goals • Team Objectives
More Examples of Visual • Signs • Charts • Goals • Pictures • Color coding • Lights • Scoreboards • VSM Current & Future State • Standard Work instructions
• • • • • • • •
Tags Forms Training hours Employees’ suggestions Cross trained skills Employee awards Absenteeism Critical maintenance points • Customer satisfaction goals • Performance targets •
Visual Controls as Communication Tools • Visual controls expose waste so we can reduce or eliminate it • Visual controls help in: – Improving motivation & morale – Focus on safety – Pride of workplace & workmanship
• Visuals and performance metrics – What gets measured, gets done – Policies drive behaviors
World Class Visual Controls • Anyone knows what’s going on by looking around • You do not have to wait for information to do your job • Everyone passes the 30 second test
Visual Examples
Andon Lights Display Panels
Range Markings On Gauges Shadow Boards
Standard Work
Reduce task variability
Standard Work
Best sequence of operations, using the most productive combination of resources:
• Man, machine, materials, changeovers, etc. • Details any special skill/knack needed • Safety, ergonomics are integrated • Tool for perfect quality and efficiency
Standard Work Properties • Specific • Measurable • Repeatable • Documented
Standard Work Identifies value added versus non-value added activities • Reduce or eliminate non-value added activities • Convert Internal Time to External Time, wherever possible • Continuous Improvement: once Standard Work is established as a base and displayed at workstations, operators monitor and implement improvements • Use as a training tool for new employees • Created by input from the people who actually work in the process
Philosophy of Standard Work Be specific about: Example: Installing a Car Seat • Content • Bolts are installed and tightened in the same • Sequence exact order • Timing • The time required to tighten • Outcome bolts is stated and followed • Specified torque is applied and checked Used as the basis from where the next level of improvement is made.
Types of Standardized Work Forms • Process Capacity Table • Work Combination Sheet • Standard Work Sheet • Others forms may be used based on your organization’s needs
Process Capacity Table Times for: • Elapsed time • Element time • Internal Time • External Time • Manual Time Step Identification • Transportation • Process • Inspection • Storage Use to identify bottlenecks Use to calculate the capacity of machines, and identify bottlenecks
Process: Seq No.
Date:
Element
Symbol
Name: Elapsed Element Internal External Time Time Time Time
Shift:
Comments
1
Review work order for die number and material
600
600
300 Convert to External
2
Locate the die
1800
1200
300 Convert to External
3
Locate material
3000
1200
300 Convert to External
4
Get tools
3600
600
5
Tagout machine
4500
900
60
Prepare Tags before
6
Loosen bolts
4980
480
60
Use quick connects
7
Disconnect hoses
5280
300
60
Use quick connects
8
Remove die from press
5580
300
120
9
Return die to Tool Room
6180
600
10
Load die into press
6480
300
11
Align die
6960
480
12
Tighten bolts
7440
480
60
13
Connect hoses
7740
300
60
14
Position material
8340
600
15
Clear tagout
8940
600
16
Make sample piece
9000
60
60
17
Take first piece sample to QC
9600
600
120
18
Adjust die and press
10800
1200
19
Make sample piece
10860
60
11460
600
20 Return tools Transport
Process
Inspection
Storage
Total Time
11460
NVA = X
Changeover Analisys Chart
300 Convert to External
Position die cart
300 Convert to External
90
Use positive stops
0 Eliminate
X
Use quick connects Use quick connects
300 Convert to External
60
Have QC Tech ready
0 Pre-adjust die
X
0 Eliminate
X
600 Convert to External
750
2400
Page ____ of _____
Work Combination Sheet Sequence of: • Manual work time • Machine operations time • Walking
Shows the interactions between machines and operators
Pr oduct Fam ily:B - Generators
ID 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
Allows to recalculate operator work content as takt time changes
Description of Work Element Manually load WC-1 Start WC-1, go to WC-2 Unload part, Load Part, Start Machine, go to WC-3 Unload part, f ile c orner, inspect to print Load nex t part, s tart machine, go to WC-1 Fas ten parts A-1, and B-1 together, go to A S-2 Fas ten Housing and Base Pac kage generator Load on c art
Total Time:
Tim e Available : 24,600
Proces s : A ssembly Cell #23 De s cription:Final Assembly Cyclical Work Ele m e nt
Percent Operator Time: Non-cyclical Work Ele m e nts
De m and: 200 Tak t Tim e : 123 Element Time Manual Machine Operation Operation Walking 12 32 0 3 0 2 1 16 2 45 120 0 2 15 3 23 41 2 42 0 0 35 0 0 5 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 168
224
41% 55% Total Cyclic Time: Seconds Time PCS
1 2 3 4 5
13
seconds
Date : January 31, 200X
piec es seconds per piece
Nam e : Eileen N. Terpris e V S M gr: I.C. Flow Graph Data
Operation Times Start 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30
44 5 19 165 20 66 42 35 9 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 44 49 68 233 253 319 361 396 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 100
0 49 68 233 253 319 361 396 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 405 200
300
400
500
3% 405 Rate
Total Time (Cyclical + Non-cyclical): Throughput per shif t = A vailable Time / Total Operating Time: Work Flow Diagram
WC-1
AS-1 Total Non-cyc lic Time:
Manual Operation Machine Operation Walking 12 32 3 0 1 16 45 120 2 15 23 41 42 0 35 0 5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
WC-2
AS-1
WC-3
AS-1
405
0 2 2 0 3 2 0 0 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Standard Work Sheet Sequence of processing steps • Worker • Machine • Tools • Layout • Material location (Standard stock)
Standard Wo
Product F
Displayed at Workstations
Continuously reviewed and updated
B - Gene
Proce
Uses • The Process Capacity Table can be used to reduce changeover times • The Work Combination Sheet can be used for line balancing when creating a cell • The Standard Work Sheet can be used for training and team development •
Standard Work Examples
Adobe Acrobat Document
Adobe Acrobat Document
Adobe Acrobat Document
Standard Work and Training Questions to ask Operators about Standard Work • How do you do this work? • How do you know you are doing this work correctly? • How do you know there are no defects? • What do you do if you have a problem? • If these questions cannot be answered satisfactorily, then either the Operator needs additional training or the Standard Work is unclear
Uses of Standard Work • Consistent performance of tasks = better quality • Track performance = actual versus standard for continuous improvement • Easy to Train = reduced learning cycle time
• New Learning Curve
Productivity
Productivity
Old Learning Curve
Time
Time
Benefits of Standard Work • Standard documentation for all shifts • Reductions in injuries and strain • Employee ownership of process • More pleasant working conditions; higher morale • Better than traditional time and motion studies • Reduced variability
Poka-yoke • Error proof (mistake proof) takes away the possibility of human error • The term Poka-yoke was made popular by Shigeo Shingo • Fail-safe devices • Low cost, highly reliable mechanisms • Detects abnormal situations before they occur, or • Once they occur, will stop the equipment from further production. The machine stoppage makes the problem visible. •
Other Poka-yoke Examples • USB ports on computers • Re-typing passwords to verify • Computer prompts before deleting file • Bar codes & scanning • ATM swipe card or beep •
Benefits of Poka-yoke • Gives immediate feedback for root cause analysis & correction (and prevention for the future). • Failure Mode and Effect Analysis (FMEA) solution can be Poka-yoke • Some examples of Poka-yoke devices are: sensors, counters, feelers, limit switches, electric eyes, probes, automatic stops.
Building Blocks of Lean Continuous Improvement & Kaizen Blitz Cellular & Pull System & TPM JIT Flow Kanban Poka-yoke
Self Inspection Batch Size Reduction
POUS Layout
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
Value Stream Mapping
See the Flow
Value Stream Analysis
Value stream analysis encompasses all activities company must do to design, order, produce, and deliver its products and services to customers – Flow of tasks, from request for service (trigger event) to service complete, from receipt of materials or information from suppliers to delivery of finished product or service to customers – From viewpoint of customer, service, or transaction – Flow of information that supports and directs both flow of materials and transformation of raw materials or information into finished goods or services Purchasing
Human Resources
Operations
Value Stream Value Stream
Finance
Sales
Purpose of Value Stream Map • Has customers’ perspective and focuses on meeting customers’ wants and needs • Starts with immediate customer and maps back to receiving inputs from suppliers and shows how fits into overall value stream • Provides single view that is a complete, fact-based, and time-based representation of stream of activities • Provides common language and view for analysis • Shows how information triggers and supports activities • Shows time for activities and whether they add value
Elements of Value Stream Map • Process steps • Value-add classification for each step • Information flow such as orders, requirements, schedules, messages, approvals, specifications, kanban signals, shipping information, standard procedures • Box score of key operational metrics including cycle time, waiting time, working time, conveyance time, distance traveled, items per shift, items processed per hour,setup time, backlog/workin-process, amount of inventory between last step and consumer, defects, cost information, resource availability and active time, process variations • Lead time is amount of time for one item to flow completely through process, noted along bottom of flow • Takt time showing customer demand rate, in upper right corner of flow
Value Stream Analysis Steps • Identify deliverable, value stream, and sponsor who has authority and responsibility to allocate resources and make changes across organization • Identify customer and value from customer’s perspective as well as regulatory, legal, and compliance requirements • Draw visual representation of process current state, generally draw steps starting at consumer’s view working back through steps to sources of material and labor; flows from left to right with time, with steps in order of occurrence • Add metrics and observations like Takt time/throughput, cycle times, defect rates, and inventory/work-in-process and information flows to identify magnitude and frequency of waste • Use lean principles to reduce or eliminate waste and reduce cycle time • Develop future state map, document steps of process that need to happen, and prioritize and implement action plans to achieve future state
Value Analysis Matrix Steps • • • • •
Structure value analysis matrix Number process steps on sub process map Have column for each process step Estimate time for each process step Place check in category for each process step, either value-add or one of non-value-add categories • Total number of hours or number of checks for each row • Report percentages of value-add and noncustomer required
Value Analysis Matrix Example Process Step
11
Time (Hours)
22
33
44
55
66
77
88
99
10 10
1212 1010 1 1 1010 2020 6 6 1010 1 1 1010 2020
√√
Value - Add Added
√√
Total
% Total
100 100
100% 100%
22
2% 2%
1010
10% 10%
Non Customer Required Internal Failure
√√
External Failure
√√
Control/Inspection
√√
Delay
66
√√
√√
6% 6%
5252
52% 52%
3030
30% 30%
Prep/Set Prep/Set-Up - Up
√√
Move
Total
√√
√√
100 100
100% 100%
RFQ Creation Value Stream Map Customer Meetings C/T = 14 days W/T = 2 days VA/T = 1 day
Iterate Assign Buyer C/T = 3 days W/T = 4 hours VA/T = ~ 0
Gather Requirements C/T = 14 days W/T = 2 days VA/T = 1 day
Verify Customer Requirements
Consult with Manufacturing Engineer
Create Preliminary RFQ
C/T = 14 days W/T = 2 days VA/T = 1 days
C/T = 5 days W/T = 2 days VA/T = 4 hours
C/T = 5 days W/T = 2 days VA/T = 1 day
Revise Triggering Event
Review and Approval Cycle C/T = 5 days W/T = 1 day VA/T = ~ 0
Continue C/T = Calendar Time W/T = Work Time VA/T = Value-Add Time
Measurable Deliverable Continue
Create Final RFQ
Review and Approval Cycle
C/T = 5 days W/T = 2 days VA/T = 1 day
C/T = 5 days W/T = 1 day VA/T = ~0
Revise
Release RFQ C/T = 2 days W/T = 1 day VA/T = 2 hours
As-Is Process Cycle Time*: C/T = 58 days W/T = ~14 days VA/T = 5 days
Assumes no revisions!
Sales Order Processing Value Stream Map
C/T = Calendar Time W/T = Work Time VA/T = Value-Add Time
Time Customer is On Telephone Initial Phone Contact C/T = 0 W/T = 0 VA/T = 0
Wait for Available Sales Person
Sales Pitch
Configure System
Fill Out Order Form
Promise to Ship
C/T = 5 minutes W/T = 0 VA/T = 0
C/T = 10 minutes W/T = 10 minutes VA/T = 10 minutes
C/T = 30 minutes W/T = 30 minutes VA/T = 5 minutes
C/T = 10 minutes W/T = 10 minutes VA/T = 5 minutes
C/T = 5 minutes W/T = 5 minutes VA/T = 0
Change Ship Date
Triggering Event Measurable Deliverable
While customer is on telephone:
Issue Work Order to Factory Floor C/T = 1 Day W/T = 1 hour VA/T = 0
Yes
MtlNo . Av ail abl e ?
C/T = 60 min. W/T = 55 min. VA/T = 20 min.
Check Availability of Materials C/T = 3 Days W/T = 1 hour VA/T = 0
From Contact to Order Launch:
Batch Together Similar Systems
Pending Order “FIFO” Queue
C/T = 6 Days W/T = 1 Day VA/T = 0
C/T = 7 Days W/T = 0 VA/T = 0
C/T = 17 days W/T = ~ 1 day VA/T = 0
Buying a Salad Process Flow Customer buys salad with salmon Processed salmon is shipped to fish markets
Restaurant supply company distributes food
Container company sells containers
Grocer offers premade salads
Salad company makes salad and delivers to grocer
Salmon is processed at fishery
Fishers catch salmon
Produce is package and shipped Meat companies process animals Manufacturers make containers
Salad company buys supplies Mother nature makes salmon
Farmers grow and harvest produce Farmers raise meat animals
Chemical producers make plastics from petroleum
Oil refined for petroleum products
Cycle Time Definition
“One of the most noteworthy accomplishments in keeping the price of products low is the gradual shortening of the cycle time. The longer an article is in the process and the more it is moved about, the greater is its ultimate cost.” Henry Ford, 1926
Work
Errors, waiting, transportation, movement etc….. Total Cycle Time
• Time that elapses from beginning to end of process • Ultimate objective or goal of Lean processes is to reduce cycle time by eliminating waste
Benefits of VSM • Helps you visualize more than the single process level • Links the material and information flows • Provides a common language • Provides a blueprint for implementation • More useful than quantitative tools • Ties together lean concepts and techniques
4 Steps for VSM 1.Determine the Product Family 2.Draw your Current State Map 3.Create the Future State Map 4.Develop your plan to get there
Current State Map • Understanding how the floor currently operates – Material and Information flows – Draw using symbols – Start with the “door to door” flow – Have to walk the flow and get actuals • No standard times • Draw by hand, with pencil and eraser – Foundation for the future state
Current State Icons Customers
Process Box Painting
Go See
Suppliers Mon., Wed., Fri. I
ShipmentTruck Inventory Push System
Operator Data Box C/T=1 sec C/O= 1 hr Rel.= 98% FPY = 95%
Cycle Time Changeover Reliability Quality
More Current State Icons
Train
Hardcopy Electronic Cell
Boat Person Plane
Fun Current State Icons ? ? ?
o
Fa x
&@#$%!
Current State Map Setup Tips •Use 11” x 17” paper, landscape •Use pencil and eraser •Draw by hand •Don’t waste time putting it on a computer just to make it look nice (non-value added time) •Practice, practice, practice Steps •Customer •Supplier •Process •Information flow •Calculate process time and lead-time
Current State Map Setup Supplier informati on
Information Flow Area
Custome r informati on
Process Flow Area
Process Time and Lead-time Area Title Block
Current State Map 2 days
PhlyeBiknight
30/60/90 Prod Ctrl Forecast MRP
Order Entry MRP
Weekly
2 Weeks
10 days
5,300 pcs/mo.
P/T = 20 min
265 pcs/day
Schedule Stamping Shared
=1
I
Deburr I
=1
C/T=1 sec
C/T=39 sec
C/O= 4 hrs
1,400
Dewey, Cheatem & Howe Daily
Daily
Spot Weld
5,425
Monthly Weekly
L/T= 2 days
Weekly Weekly
I
20 min
Assemble I
=1
1,225
=2
C/O= 11 min
C/T=17 sec C/O= 0 min
C/T=48 sec C/O= 5 min
Rel.= 98%
Rel.= 99%
Rel.= 80%
Rel.= 100%
FPY = 95%
FPY = 90%
FPY = 100%
FPY = 98%
1 sec
20.5 days
39 sec
5 days
17 sec
4.5 days
48 sec
40 days 105 sec
Future State Questions 1. What is the Takt Time? 2. Will we build to shipping or to a supermarket? 3. Where can we use continuous flow? 4. Where do we have to use supermarket pull system? 5. At what single point in the production chain do we trigger production? 6. How do we level the production mix at the pacemaker process? 7. What increment of work will we release and take away at the pacemaker process? (Leveling the volume) 8. What process improvements will be necessary? (e.g. uptime, changeover, training)
1. What is the Takt Time? • Takt means drumbeat • Ability to meet customers’ demand
• Formula
Takt Time =
Time Available Demand
Takt Time Calculation Time available Shift (8 hours) = 480 mins Breaks (2 x10) - 20 mins Lunch - 30 mins Meetings 5 mins C/O 5 mins Total Time = 420 mins = 25,200 sec Demand = 265 parts Takt Time = 95 sec/part
Takt Time Calculation • Takt Time = Demand Rate – Goal: Produce to demand with no excess capacity • Takt Time = work time available number of units sold • Assume 5 people work, sell 500 units/week: – TaktTime = (5 x 40 x 60) / 500 = 24 min/unit – Set cycle time to match personnel/operation
Exercise • Takt time calculation
Takt Time Calculation • Old requirements: 847/day * 240 workdays/yr = 203,000/yr • 10% growth = 223,600/yr • New requirements: 223,60/yr/240 workdays/yr = 931/day • Time available: 8.5 hrs/day - .5 hrs (lunch) - .33 hrs (breaks) = 7.67 hrs/day • 3,600 secs/hr * 7.67 hrs/day = 27,612 seconds/day • 27,612 seconds/day divided by 931 units/day = 29.3 secs per unit • Cycle time (actually 116 secs/unit) divided by Takt time (29.3 secs/unit) = 3.95 = 4 operators required •
Quick Changeover
Changeovers in less than 10 minutes
Quick Changeover • Factory definition – the time from the last good piece of previous run to the next good piece of new run • Office definition – the time it takes to switch from one task to a new task – Typically, in the office the time savings is not as significant as in manufacturing
2 Hour C/O – Large Batch Size 8 7 6 5 4 3 2 1 0
A Mon
B Tue
W ed
C Thu
D Fri
E
1 Hour C/O – Half Batch Size 8 7 6 5 4 3 2 1 0
B
D
A
C
E
A
C
E
B
D
Mon
Tue
W ed
Thu
Fri
10 Minute C/O – Small Batch Size 8 7 6 5 4 3 2 1 0
E
E
E
E
E
D
D
D
D
D
C
C
C
C
C
B
B
B
B
B
A
A
Mon
A
Tue
Wed
A
Thu
A
Fri
10 Minute C/O – Many Different Small Batches 8 7 6 5 4 3 2 1 0
D
D C E
B E F
B
C
A
H
C B
B Mon
D
Tue
Wed
F
A Thu
G
H Fri
A
G B
I
Changeover Summary Based on per week C/0 Time Number of 40 hours Number of Production Changeovers Production Time Runs Available
2 Hour
5
5
30 hours
1 Hour
10
10
30 hours
30 Minute 15
15
32.5 hours
10 Minute 25
25
35.8 hours
SMED • Single Minute Exchange of Dies (SMED) • Shigeo Shingo (1970) 1.Separate internal steps and external steps 2.Convert internal steps to external where ever possible 3.Streamline all steps •
4 Categories of SMED time 1. Preparation, afterprocess adjustments, checking of material and tools (30%) 2. Mounting, removing tools and parts (5%) 3. Measurements, settings and calibrations (15%) 4. Trial runs and
30%
5% 15%
50%
Typical proportions
Step 1. Separate Internal and External Times • Checklists • Functional checks • Transportation of parts and tools
Step 2. Convert Internal Time to External Time • Preparation conditions – Pre-heat, correct air pressure, stage materials
• Standardize – Centering, gripping, securing, replace fewest parts, standardize heights, standardize bolts or fasteners
• Intermediary jigs – Mounting plates
Step 3. Streamline • Parallel operations – More than one person working at the same time
• Eliminate adjustments – Markings – Scales
• Functional clamps • Mechanization
Changeover Cart Example
Before • Waste of time to find correct tools • Tools can become damaged • Waste of money for extra tools
After • Saves time • Do not have to replace tools as often • Have what you need where its needed
QCO and Other Building Blocks • 5S, Visual, POUS, Teams and Standard Work • VSM can discover opportunities for QCO • As Batch Size Reduction continues, QCO becomes more important • Kaizen Blitz is a great method to implement QCO • Must sustain the gains
Benefits of Quick Changeover • Shorter lead time • Less material waste • Fewer defects • Less inventory • Lower space requirements • Higher productivity • Greater flexibility • Better Teamwork
Building Blocks of Lean Continuous Improvement & Kaizen Blitz Cellular & Pull System & TPM JIT Flow Kanban Poka-yoke
Self Inspection Batch Size Reduction
POUS Layout
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
Continuous Improvement Kaizen vs. Kaizen Blitz, or Incremental vs. Breakthrough Improvements Kaizen Incremental Improvements: • Are continuous, since there is always room for improvement in any process • It is never-ending • Many small improvements throughout the enterprise • Done by individuals or small teams • Could be functional, departmental, or task-oriented • Part of the “useful many” • A little time spent on an ongoing basis • Standardization of processes (i.e., process improvement oriented) • Plan-Do-Check-Act methodology
Continuous Improvement
Ideas for continuous improvement could come from: – – – – – – – – –
•
Employee suggestions Corrective & Preventive actions Non-conformities, defects Customer complaints, returns Benchmarks The Lean “wastes” Variations from the standard Assessments, audits & competitive analyses Research & Development activities
Continuous Improvement & Continuous Learning
• Continuous Learning goes hand in hand with continuous improvement • Management should have training given to employees in Lean and Quality tools, problem solving and root cause analysis, the process model, concepts of Theory of Constraints, basic statistical techniques, graphical tools, etc. • Understanding of Plan-Do-Check-Act and Standardize-Do-Check-Act (SDCA) will be beneficial
Continuous Improvement & Continuous Learning
• Continuous improvement and learning: – Becomes part of daily work life – Is practiced at both personal, functional and organizational levels – Is result oriented – Is shared within the enterprise – Becomes part of institutional memory and knowledge, even after employees retire, move up/laterally or leave
Why C. I.? • Standing still is not an option: – – – – –
Competitors will overtake us Globalized economy Higher customer expectations Technical and breakthrough changes Tapping into human potential and creativity
• Improvements based on: – – – – –
Cost and cycle time reduction “Waste” minimization Defect prevention Enhancing customer satisfaction/delight Attaining competitive advantage
Kaizen Blitz
• Breakthrough strategies for lasting results
Building Blocks of Lean Continuous Improvement & Kaizen Blitz Cellular & Pull System & TPM JIT Flow Kanban Poka-yoke
Self Inspection Batch Size Reduction
POUS Layout
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
Kaizen Blitz • Kaizen Blitz is a combination of the Japanese word Kaizen for “continuous improvement” and the German word Blitz for “lightning.” It is a focused, week-long workshop where a cross-functional team reviews a process, identifies and eliminates waste, thereby achieving dramatic and tangible breakthrough (rather than incremental) improvement results. • Kaizen Blitz now stands to mean the improvement activity itself. • It is treated more as a “Project” (rather than a “Process”).
Why Kaizen Blitz? • Major benefits in a flash. • Can use benchmarking for setting goals. • Innovation has become indispensable in today’s competitive world economy. • Cycle Time Reduction translates directly to cost savings. • Kaizen Blitzes typically attack wasted time. • Positive impact on organizational culture through “breakthrough” type improvements.
Who Will be Involved? • Kaizen Blitz teams that come together for one week to implement improvements in a pre-selected bottleneck project or process. • Cross-functional teams (seven to ten persons) • Hourly and salaried personnel • Operators, engineers, supervisors, maintenance persons, managers, technical experts, material handlers, quality personnel, business support personnel, participants from the outside • Typically, the Team Leader is person with clout and is the highest stakeholder in the process who possess leadership skills, open minds, strong desire to succeed and some prior Lean experience.
Kaizen and Cycle Time Reduction • • • •
Focus on Process. Focus on Elimination of Waste. Focus on Speed. Time improvement translates directly to cost savings and customer satisfaction.
Kaizen Blitz Steps 1.Select specific area for improvement. 2.Define current situation in measurable terms 3.Set aggressive goals (stretch goals). 4.Identify team members. 5.Conduct training on the first day of the project. 6.Do it (in three to five days).
Step 1 – Select Project • • • • • • •
Value Stream Map Bottlenecks Customer or quality related issues Interdepartmental Long lead-times or setup times Competitive advantage Cost reduction or avoidance
Step 2 – Define Current State • • • • •
Video tape Time study Flowchart Historical information Observations and interviews
Step 3 – Identify Team Members • Cross-functional teams (seven to ten persons) • Hourly and salaried personnel • Operators, engineers, supervisors, maintenance persons, managers, technical experts, material handlers, quality personnel, business support personnel, participants from the outside • Typically, Team Leader is person with clout and is the highest stakeholder in the process. Ideally, the team leader must possess leadership skills, open minds, strong desire to succeed and some prior “Lean” experience.
Step 4 – Set Aggressive Goals • Define the purpose or objective and set stretch goals. • Goals should be clearly defined and quantifiable (e.g., reduce machine set up time by 75%, increase throughput by 40%, reduce floor space by 30%). • Emphasis should be on identifying and eliminating waste, and then standardizing at the improved level. • Benchmark when possible
Step 5 – Conduct Training • Select hands-on training that is compatible with the project • Do training on the first morning • Provided by an internal or external expert
Step 6 – Do it!
• Perform in 3 to 5 days
Example 1 – Universal Joint QCO Category
Changeover
Tool Change
Target savings 4.9 hours (75%) 14.8 hours (75%) Actual savings 4.5 hours (69%) 13.8 hours (70%) Target savings $291 per day
$879
Actual savings $268 per day
$820
Total savings
$272,041 per year
Example 2 – Tube Mill SMED • Changeover savings per year: $510,000 • Reduced changeover time from 4 hours, 40 minutes to 2 hours, 11 minutes • Employees happier – bonuses based on changeovers • Management happier – more changeovers, more production, more cash in the door
How to Start and Sustain your Lean Journey
• A journey of one thousand miles, starts with a single step
8 Ways to Get Started 1.Baseline Assessment or Gap Analysis 2.Value Stream Map 3.Training in Lean 4.Basic Building Blocks 5.Kaizen Blitz 6.Pilot Projects 7.Change Management 8.OEE •
1. Baseline Assessment Baseline Assessment or Gap Analysis performed by experienced Lean experts • Use
– – – –
Interviews Observations Process mapping Analysis of reliable data
• Create a “Gap Analysis” with focus on eliminating the Eight Wastes • Generate an Action Plan for implementing Lean improvements
2. Value Stream Mapping Value Stream Mapping • Assemble the cross functional team • Have a Value Stream Manager • Determine a Product Family • Create the Current State Map • Create the Future Stats Map • Develop the Plan to get there, tie-in with business objectives • Review the Plan, stay on course • Your Future State then becomes your Current State • Expand to Multiple Value Streams
•
3. Training in Lean Training in Lean
• “Massive” training in Lean • Need to build a critical mass of trained employees • Perform the training just before implementation • Lean Champions should have advanced skills in Lean •
4. Basic Building Blocks • Start with one of the Basic Building Blocks of Lean • • Continuous Improvement & Kaizen Blitz TPM
JIT
Poka-yoke POUS
Cellular & Flow Self Inspection
Batch Size Reduction
Layout
Pull System & Kanban
Standard Work
Change Management
Autonomation
Quick Changeover Visual
5S Teams
V S M
Basic Building Blocks Basic Building Blocks • Start with the implementation of the Basic Building Blocks • Build up layer by layer until TPM, Cellular Manufacturing and Pull/Kanban are established • Then continuously improve using Kaizens, suggestion systems and periodic Value Stream Maps. • •
Example – Implementing 5S • Plan – Identify 5S Champions & Teams – Decide how to rollout to entire organization – Resources required
• Train – Train just before Kaizen – Train-the-trainer
• Do • Improve & Repeat
5S Implementation Map 8 9 7 8 8 9 9 10 13 8 8 9 9 10 5 1 4 2 11 1 1 1 4 3 5 6 12 4 4
5. Kaizen Blitz Select a Kaizen Blitz project • Perform in 3-5 days • Focus on speed and elimination of waste • Can perform on “low hanging fruit” • Generates quick victories and improvements • Do not continue in an Ad-hoc approach, use your Value Stream Map
6. Pilot Projects Pilot Projects • Implement Lean Pilot Projects where bottlenecks have been identified • Use cross-functional teams • PDCA methodology is best • Can use benchmarks and best practices for goal setting • Communicate results • Migrate lessons learned to other areas • •
7. Change Management Change Management
• Begin with cultural Change Management before rolling out Lean • Address the human side of Lean in your three to five year Master Plan • Use internal/external change agents • Communicate the need for change: ultimately, Lean has to become integrated into daily work life • Open up channels for sharing ideas •
8. OEE Overall Equipment Effectiveness (OEE) analysis can identify where to start your Lean journey • Pareto the time spent on:
– – – – – – – –
Breakdowns Setups Tool changes Idling time Slower speed Minor stoppages Producing defects, rework Start-up issues
• This exercise will self-identify the “biggest bang for the buck” and where to start
Plan • You must have a plan • Utilize a Steering Committee, Design Teams and Lean Champions • Tie the Lean Objectives with the Business Objectives • Commit resources (time, people, budgets)
Stages of Lean Implementation Generally, organizations can use this model for the stages of implementing Lean
• Takt – Establish takt time and meet it
• Flow – After meeting takt time, then create Flow
• Pull – Where you can’t Flow, Pull
How to Sustain Lean? • Lean will not be sustainable without proper training in Lean and satisfied employees • Internalize into daily work • Understand that it is a never-ending process or philosophy: no turning back • Create discipline/motivation/incentives • Standardize so as not to slip back
How to Sustain Lean? • Continued, visible management commitment • Open communication channels • Emphasize accountability • Use Lean performance metrics • Role of Lean champions • Job rotation
How to Setup the Lean Team
• Steering Committee • Design Teams • Champions
Lean Team Roles & Responsibilities Design Team 5S, Visual, POUS Design Team
Champions
Lean Steering Committee
Cellular Design Team
Champions
HPT Design Team Pull/Kanb an Design Team
Champions
Steering Committee Roles & Responsibilities • Set the Lean policy • Provide resources – time, people, Lean Steering budgets & remove barriers Committee • Develop and share the Lean Vision • Develop the Communication Plan and then deploy it • Members usually • “Walk the talk” everyday and fully from top support the Lean initiatives management, but can include “Value • Determine the Design Team makeAdders” up and members • Review the work of the Design Teams
Design Teams Roles & Responsibilities • Deploy the Lean policy • Determine the resources required – Time, people, budgets, etc • Determine the best way to implement the Lean Building Blocks in your organization • Report to the Steering Committee on progress • Support your Lean Champions
Design Team
• Members usually from management or “Value Adders” • Group like Building Blocks together
Design Team Agenda • Design Teams decide how • Design Teams may change Lean will be implemented over time at their facility – At first they oversee • Take into account: the implementation plan – Organizational Culture – Then they support the sustaining – Change management efforts – Resources – They may disband, – Current skills & be absorbed into needed skills another Design – Size and timing of Team or morph projects into a new design Team – Metrics & Goals
Lean Champions Roles & Responsibilities • Deploy the Lean policy via training, implementation and Kaizen Blitz • Feedback information to the Design Team on progress • Be given the time to support the Lean efforts • Make presentations and communicate the results of the Lean projects
Champions
• Members usually from management or “Value Adders” • Motivated to learn, lead and improve their organization
Champion’s Agenda • Be ready to commit time to Lean projects • Be willing to learn and continually improve • Become a Lean content expert • Have skills in training, public speaking, project management and be a team
WIIFM
• Gain new skills • Valued by the organization • Exciting, new assignments • Learn other aspects of Lean
Multi-facility Deployment Example Small Facility Lean Steering Committe e Design Team/ Champio ns
Organizat ion Lean Steering Committe e
Desi gn Tea m
Desi gn Tea m Champions
Large Facility Lean Steering Committe e Desi Desi gn gn Tea Tea m m
Momentum • Have to build a “critical mass” of employees trained in Lean and apply principles • Build “buy-in” and get people onboard • “Bandwagon” affect
Organizational Alignment
Dealing with Objections to Lean • Put yourself in their shoes • Help answer “WIIFM” • Communicate, communicate, communicate and then communicate some more! • Create an “Elevator Speech” •
Getting People on Board se i d a r a P Lean
!
?
Status Quo Land
Lean Enterprise vs. Lean Manufacturing
• Taking Lean beyond the shop floor
Lean Enterprise • Move from the shop floor to Enterprise-wide Lean implementation • Many of the Building Blocks are essential for efficient office functions – 5S, Visual, POUS, Standard Work, Layout, Self Inspection, Pokayoke • The goal is to reduce or eliminate the wastes to reduce lead times and to enhance responsiveness, competitiveness and customer satisfaction •
Thank you! www.asq.org
View more...
Comments