Automated Drilling Machine

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Dr.MAHALINGAM COLLEGE OF ENGINEERING & TECHNOLOGY

DEPARTMENT OF MECHANICAL ENGINEERING PAPER TITLE: ROBOTICS AND AUTOMATION

Submitted By Danagovardhan.C

1 ABSTRACT

For cylindrical objects with requirement of radial and axial drilling conventionally the radial drilling shall have to be done by CNC lathe if it is to be of accurate dimensions. The axial drilling requires a four axis machining center for carrying out diametrical as well as a lengthwise drilling. Otherwise jigs and fixtures have to be used. If the pitches between the holes vary then jigs and fixtures design has to be changed. With the advent of servo technology the precise motion as good as CNC machine is possible. It is now easy to build a special purpose machine to do this job above exclusively where volumes are involved. The special purpose machine for it to be accurate has to employ servo system for bringing in accuracy and precision. This project aims to built a special purpose drilling machine, which will have the capability to make drill holes of different gaps both diameter wise and lengthwise. The project will have a human machine interface through which the number of holes requires and diameter wise, the gap between holes etc. could be entered by the operator. This data will be transmitted to a programmable automation controller, which will have the capability to do motion control operation. The programmable automation controller will be driving two servo motors for indexing diameter wise. As per the data entered in the HMI, the PAC will generate motion commands to the servo systems and accurate drilling will occur. A home position sensor and over travel sensor is provided to create reference positions and to avoid over travel condition. By doing this project a low cost machine is to be built instead of employing high cost CNC machine and multimachine operation is replaced by a single machine operation. 1. INTRODUCTION

Today, the manufacturing leaders like China, Japan, Korea and America who leads the world, produces the major products in the world market. India, as an emerging country lags behind these nations. The reason behind this is the majority of the industry comes under SME (Small and Medium Enterprise). Their production rate is not higher because of lacking in automation technology. Even some of the industry feels difficult to go for advanced CNC machines. In this project we incorporated the integrated architecture of a special purpose automation process. The PAC, Motion Controller and

2 the PC are entirely connected through network and enhance the data transfer and feedback signals. This integrated architecture has been tested for drilling a cylindrical component by fabricating a Special Purpose Drilling Machine. The cylindrical components that are used for testing has been merged for two application. The material and size of the component is for agriculture and water applications. The profile that we tested covers some complex application like holes in Roller Stroke Bearing. In general the usage of cylindrical components is seen in many fields. These components that are used in various industries are listed and discussed. On analyzing all the components based on their varying profiled hole. The skeleton or layout of the projects with its entire architecture is explained below. The various interface used in our prototype all pictured vividly. The various mechanical components that are present in the machine are drawn in CAD. The various views of entire architecture are drawn in CATIA. It includes how PAC is connected and also explains the data transfer between various modules. It also includes integration has been quoted for further development. 2. LAYOUT OF MACHINE 2.1 GENERALIZED BLOCK DIAGRAM

The elements involved in the automation process belong to the brand name of  ALLEN BRADLEY. The following components are also used that are PC (Personal Computer), PAC (Programming Automation Controller), Motion Controller, Axis Drivers, DC motor, DC servomotors. The actual layout of the automation process is shown below. The diagram shows the working of the Automated Special Purpose Drilling Machine.

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FIG 1 BLOCK DIAGRAM OF AUTOMATED DRILLNG MACHINE

2.2 WORKING METHODOLOGY

Step 1

The user will directly enter the values of the required parameters

through PC. Step 2

The parameters which are entered in the HMI will transmitted to

PLC and stored in its TAG memory. Step 3

The TAG memory will be accessed by the Motion Controller.

Step 4

Based on the values entered the Motion Controller will control Z -

axis, Y – axis Y’ – axis through its respective drives.

2.3 SPECIFICATIONS

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2.3.1 SERVO MOTOR

The specifications of the servo motor are as follows. Maximum speed Power rating

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3000 RPM

0.46 kw

Continuous amperes -

3  – 20 amperes

Ambient temperature -

40 degree

RMS Voltage

230 V/3 PHASE

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Insulation class Frequency

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H  – CLASS (180 )

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0  – 200 HZ

PAC

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Programming Automation Controller

Brand

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Allen Bradlley

Family

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Control logix 5560

Analog Input

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1756 0F8

Analog Output

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1756 1F8

Input Module

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1756 1B 16 (DC)

2.3.2 PAC

Output Module

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1756 0B 16 (DC)

Motion Controller

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1756 MO3 SE

Software Used

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RSLogix 5000

3. MECHANICAL COMPONENTS 3.1 Lead Screw

The lead screw is a long threaded shaft used as s master screw to convert the rotary movement into linear movement. The input power is from the servo motor and the actuation is that it actuates or gives the the table movement. There is a nut housing which connects the lead screw and the table. The pitch of the

5 screw is 2 mm and the diameter of the lead screw is 25 mm.

Material

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Steel

Size

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Ø 25 × 700 mm

Pitch

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2 mm

Thread Length -

350 mm

Quantity

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1

3.2 BEARINGS

Bearings are most commonly used for resist wearing and also used for easy movement because of reducing friction. Some types of Bearings are used below. They are 1 Linear Motion Bearing 2 Pillow Block Bearing 3 LM Bearing Housing 4 Rectangular Hollow Block 

3.3 DRILLING MACHINE

Normal drilling machine used, which are using in now a days. 3.4 COLUMN

The Column is also called pillar. The column is the vertical member of the machine which supports the drill containing all the driving mechanisms. The column should be sufficiently rigid so that it can take up the entire cutting pressure of the drill. In this machine the vertical column is a hollow cylinder. 3.5 DRILL HEAD

The drill head is mounted on the top of the column and houses the driving and feeding mechanism for the spindle. The drill head consists of the spindle motor, step cone pulley and belt drive for speed reduction, spindle and collet chuck. The feeding mechanism of the spindle has rack and pinion arrangement, which is used for converting linear movement to rotary movement.

6 3.6 COLLET CHUCK

The collet chuck is held at the end of the spindle and in turn it holds the drill bit. The Collet chuck consists of three jaws which can be moved in and out of a V channel. When screwed in clockwise direction in the jaws will move up and make a clamp. The  jaws will unclamp when rotated in anti clockwise direction.

3.7 TIMING PULLEY AND BELT 3.7.1 Lead Screw Timing Pulley

FIG 2 LEAD SCREW TIMING PULLEY

Bore Diameter of Driver  – 16 Outer Diameter of Driver  – 26 Bore Diameter of Driven  – 20 Outer Diameter of Driven  – 80 (maximum) Center to center Distance of Driver and Driven  – 180 mm Pitch – XL Size – 9.56 mm Breadth of the Timing Belt  – 25 mm 3.7.2 ROLLER TIMING PULLEY

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FIG 3 ROLLER TIMING PULLEY

Bore Diameter of Driver  – 16 Outer Diameter of Driver  – 26 Bore Diameter of Driven  – 24 Outer Diameter of Driven  – 80 (max) Center to center Distance of Driver and Driven  – 180 mm Pitch – XL Size – 9.56 mm Breadth of the Timing Belt  – 25 mm 4.1 ELECTRICAL COMPONENTS

This machine has a electrical components for driving the Automated Drilling Machine. The electrical components forms an integrate part of the structure. The Automated Drilling Machine has sensors for controlling the machine accurately by giving some feed backs. The following are the electrical components in the drilling machine. 1 AC Induction Motor 2 DC motor 3 Servo motor 4 Micro switches 5 Limit switches 6 Control Relays

8 4.1.1 SERVO MOTOR

The servo motor is used in the drilling machine for driving two parts namely, Work holding roller and Table. The servomotor drives the roller and the table through the timing pulley and belt. The servo motor used is KINETIX of ALLEN BRADELLY. 4.1.2 MICRO SWITCHES

Micro switches are used in the drilling machine to sense the position of the spindle. It senses the position and gives feed back to control the up down motion of the spindle by reversing the direction. The distance between the micro switches is determined by the depth of the drill.

4.1.3 LIMIT SWITCHES

Limit switches are used in the Automated Drilling Machine to sense the position of the table. It gives the control signals to control the table from over travel and for attaining a reference or home position. The feed back is given to the controller thus it ultimately controls the motor. The limit switch is actuated by the nut housing of the table. The distance between limit switches is determined by the length of the work piece. 4.1.4 CONTROL RELAYS

Control Relays are used in the drilling machine to change the direction of the DC motor which is used to drive the spindle up and down. The rating of the control relay is 24V. 5. WORKING OF THE MACHINE The fabricated model is 3 axis system. The each axis and its function is mentioned below. Z – Axis

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Spindle Movement

Y – Axis

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Linear movement of the table

Y’ – Axis

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Indexing of work piece

5.1 Z - AXIS MOVEMENT

9 Z  –  Axis is the spindle movement axis along which the drill bit extends before drilling and retracts after drilling. The spindle movement is being controlled by a 12 v DC motor. The chain drive is used to connect between spindle shaft and the DC motor. The limit switches are placed near the spindle for controlling the depth of a hole. The limit switches sends to the PLC and in the sense PLC acts accordingly. 5.2 Y – AXIS MOVEMENT

Y axis is the linear movement of the table over which the work piece is mounted. The linear movement of the table is controlled by a separate AC servo motor. The servo motor drives the power screw which is attached to the table. The power from the servo motor is transmitted to the power screw through the timing belt and pulley. This linear movement is necessary for drilling next series of holes in the work piece. The linear movement of the table is achieved by sliding action over the shaft which is mounted over the base table. The smooth sliding of the table over the shaft is performed by means of a Linear Motion (LM) Bearing which is fixed to the table. 5.3 Y’ – AXIS

MOVEMENT

Y’ axis movement is the indexing of the work piece. It is a rotational movement about Y’ axis. This indexing is done by a separate PLC controlled AC servo motor. The

servo motor rotates to the required angle after each drill is made. The servo shaft is connected is to the work piece shaft by means of a timing belt and pulley. The servo motor is attached to the work piece table itself.

10 FIG 4 FABRICATED MODEL OF THE MACHINE

6. CONTROL SYSTEM 6.1 CONTROL LOGIX

Control Logix is a PAC (Programmable Automation Controller). It is a modular type PAC. It consists of SERCORS Interface module. The SERCORS module links the ultra 3000 servo drive with the control logix controller. It can link up to 8 servo drives with the controller. The module uses fiber optic cables for all field side wiring. It is programmed through RS LOGIX software.

11 7. APPLICATION

On surveying the industry, the usage of the cylindrical components is seen more. The application covers wide field and have lot of advantages. The most common fields that depend upon such cylindrical components are listed below. The most commonly used component in these fields is ROTARY STROKE BEARINGS. This bearings act well in guiding any element linearly with most efficiently. The bearing consists of ball in its circumference and the CAD model with holes.

7.1.Mechanical Engineering

The high precision rotary stroke bearing is most popular in mechanical engineering applications. It is used for die cutting and moulds in tool building applications and in machine tools where it is used, for example, for center sleeve bearings. It is an indispensable component for packaging machines in a wide range of  industries, in automatic assembly units, textile machines and high quality special purpose machines. 7.2 Precision Engineering

The degree of miniaturization in these industries requires compact instruments. Rotary stroke bearings in the mini series satisfy this need. Small ball diameters reduce the installation space required. The “minis’ come in pair and do not have play and are

essential for world wide range of applications including small control elements for placer heads and laser welding technology as well as blade holders, jigs or fixtures. Stick slip freedom, easy movement and maintenance free operation are all important. 7.3Medical Technology

Medical equipment is subjected to particularly high standards. In dental technology, rotary stroke bearings are therefore used in freehand milling machines for machining soft materials, the requirements on apparatus that come into contact with patients are even higher. In the case of ophthalmologic instruments, the stick slip free rotary stroke bearing supports the doctor’s touch and experience.

12 7.4 Electronics and Optics

The production of electronic components requires machines that are able to approach positions with accuracy at high speeds. High precision rotary stroke bearings are crucial components in printed circuit board production and lithographic processing of  wafers. This is also true of optical metrology, microscopy, spectrography and lens guides in different areas of application. Stick slip free movement and absolute cleanliness are vital. 7.5 Engineering Metrology

In the field of industrial metrology, high precision rotary stroke bearings are used in probes and dial comparators, positing units, centering and tilting tables and in other modules that have an influence on the measuring result. High precision rotary stroke bearings must exhibit no backlash, Stick slip or wear and the motion must be smooth and reproducible.

7.6 Textile Industry

Dust Absorber Regarding the textile industry, the usage of cylindrical components as seen is explained as follows. It is seen in the blow room unit of the spinning industry. The purpose of the blow room unit is to remove dust particles present in the raw cotton.

7.7. Water Purifier

One of the cylindrical components that observe is drilling a hole in the circumferential face of the job. The component is being used in the irrigation for filtering the water and in the case of bore well. The time to produce one component is nearly 45 minutes.

8. CONCLUSION

In this paper, the Integrated Architecture has been tested with a cylindrical components drilling, will useful as a Automated Drilling Machine. The model which have been fabricated and the application that it will fit for has its own limitations. In this method the values are entered by the user through the PC only. The alternate method by which the values can be passed to the PAC is through Human Machine Interface. The

13 user can directly involve with the GUI (Graphical User Interface). On further this software can be developed as a web based one through which many users can interact with the PAC from online. This can be achieved through Ethernet module.