CAM 3E PowerPoint Slides to Chapter 01

1. Introduction

Understand the various spheres of manufacturing activity where computers are used What is meant by product cycle with the differences between the conventional and computer based manufacturing systems Definitions of various computer based applications Discuss various facets of the design process Computer Aided Design and its applications Various types of manufacturing organisations Computer Aided Manufacturing and its application Meaning of Computer Integrated Manufacturing 

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Computer monitoring and control of the manufacturing process. Manufacturing support applications, which deal essentially with the preparations for actual manufacturing and post-manufacture operations. 

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CAD - computer aided design. The use of computer methods to develop the geometric model of the product in threedimensional form, such that the geometric and manufacturing requirements can be examined. CADD - computer aided design and drafting. Combining the CAD function with drafting to generate the production drawings of the part for the purpose of downstream processing. CAE - computer aided engineering. The use of computer methods to support basic error checking, analysis, optimisation, manufacturability, etc., of a product design. 

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(c) TMH New Delhi, CAD/CAM Principles

CAM - computer aided manufacturing. Generally refers to the computer software used to develop the Computer Numerical Control part programs for machining and other processing applications. CAPP - computer aided process planning. The use of computer to generate the process plans for the complete manufacture of products and parts. CATD - computer aided tool design. Computer assistance to be used for developing the tools for manufacture such as jigs and fixtures, dies, and moulds. 

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(c) TMH New Delhi, CAD/CAM Principles

CAP - computer aided planning. The use of computer for many of the planning functions such as material requirement planning, computer aided scheduling, etc. CAQ – Computer Aided Quality assurance. The use of computers and computer controlled equipment for assessing the inspection methods and developing the quality control and assurance functions. CAT – Computer aided testing refers to the software tools that can take a system through its various phases of operations and examine the response against the expected results. 

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(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

Design is an activity that needs to be well organised and should take into account all influences that are likely to be responsible for the success of the product under development. 

(c) TMH New Delhi, CAD/CAM Principles

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Product Engineering          

Product functions Product Specifications Conceptual design Ergonomics and Aesthetics Standards Detailed Design Prototype development Testing Simulation Analysis

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Manufacturing Engineering           

Process planning Process sheets Route sheets Tooling Cutting tools Jigs and Fixtures Dies and Moulds Manufacturing Information Generation CNC Part programmes Robot Programmes Inspection (CMM) programmes (c) TMH New Delhi, CAD/CAM Principles

Problem identification and recgnition of need

Problem definition and conceptualisation

Geometric modelling and spatial analysis

Engineering analysis and optimisation

Prototype development

Manufacturing process development Manufacturing Implementation (c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

During the operation of the product, does the part move relative to all other parts already assembled? Must the part be of a different material than or be isolated from all other parts already assembled? Must the part be separate from all other parts already assembled because otherwise necessary assembly or disassembly of other separate parts would be impossible? 

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Use standard processes and methods. Limit the manufacturing processes to those already available and that the plant has expertise in. Reduce the variety of manufacturing processes used. Use standard (off the shelf) components in the design. Provide liberal tolerances such that overall manufacturing cost could be lowered. Use materials that have better manufacturability. Since many of the secondary operations require additional cost, they should be minimised or avoided. The design process should be commensurate with the level of production expected of the part. When a particular process is identified, exploit the special features of the process to get better economies.  

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(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

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Layout design for the overall assembly Individual component modelling Assembly modelling Interference and tolerance stack checking Engineering drawings

(c) TMH New Delhi, CAD/CAM Principles

Computer aided design (CAD) is faster and more accurate than conventional methods. The various construction facilities available in CAD would make the job of developing the model and associated drafting a very easy task. In contrast with the traditional drawing methods, under CAD it is possible to manipulate various dimensions, attributes and distances of the drawing elements. This quality makes CAD useful for design work. Under CAD you will never have to repeat the design or drawing of any component. Once a component has been made, it can be copied in all further works within seconds, including any geometric transformation needed. 

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(c) TMH New Delhi, CAD/CAM Principles

You can accurately calculate the various geometric properties including dimensions of various components interactively in CAD, without actually making their models and profiles. With the constraint based modelling methods that are prevalent in most of the commercially available CAD systems, it is possible to capture the design intent into the product model beyond the simple geometry. This will help in actually making modifications easily. Also it is possible to try various options, thereby optimising the whole design process. Thus the geometric modelling process can be driven by the physics of the process. 

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Modification of a model is very easy and would make the designer's task of improving a given product simple to take care of any future requirements. Use of standard components (part libraries) makes for a very fast model development work. Also a large number of components and sub-assemblies may be stored in part libraries to be reproduced and used later. Professional CAD packages provide 3D (3 dimensional) visualisation capabilities so that the designers can see the products being designed from several different orientations. This eliminates the need of making models of products for realisation and explaining the concepts to the team. 

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(c) TMH New Delhi, CAD/CAM Principles

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Mass production ─ large lots e.g. automobiles Batch production ─ medium lot sizes e.g. industrial

machines, aircrafts, etc.  Job shop production ─ small lots or one off, e.g. prototypes, aircrafts, etc. 

(c) TMH New Delhi, CAD/CAM Principles

(c) TMH New Delhi, CAD/CAM Principles

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Greater design freedom Increased productivity Greater operating flexibility Shorter lead time Improved reliability Reduced maintenance Reduced scrap and rework Better management control

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The synergy can be obtained by integrating all the functions in manufacturing through the computer such that all the incremental improvements that are possible can be improved manifold. That is what is normally termed as Computer Integrated Manufacturing or CIM. 

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Large amount of waste in traditional production methods Japanese manufacturers have recognised this fact, and developed methodologies that lead to the reduction of waste during the mass manufacturing operations. 

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The UK Department for Trade and Industry defines Six Sigma as "A data-driven method for achieving near perfect quality. Six Sigma analysis can focus on any element of production or service, and has a strong emphasis on statistical analysis in design, manufacturing and customer-oriented activities." 

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