3. Goal: Understand the stages in design process and the role of computer aided design. Objectives: After this chapter, you should understand the following concepts:  Understand the various spheres of manufacturing activity where computers are used.  Definitions of various computer-based applications  Various facets of the design process  Computer Aided Design and its applications  Computer Aided Manufacturing and its applications

4.  The need of following requirements  the use of low-cost but powerful computers:  Quality manufacturing  Short lead times  Short product lives  Increasing awareness of consumer for quality product  The influence of computers in manufacturing environment is shown in next slide.  The role of computers in manufacturing:  Computer monitoring and controlling of the manufacturing process Monitoring and controlling functions in manufacturing  Manufacturing support applications Related to actual-manufacturing and post-manufacturing operations  C omputer monitoring and controlling of the manufacturing process  Build-in specifications in computer memory initiates suitable actions for the purpose of regulating process through the monitor of parameters. Alternately, this can be done by a human operator

5. Computer Aided Design (CAD) Manufacturing Systems Computer Aided Manufacturing (CAM) Business Data Processing System

6. Manufacturing Support Applications The use of computers:  CAD (Computer Aided Design) – To develop geometric model of the product such that the geometric and manufacturing requirements can be examined.  CADD (Computer Aided Design and Drafting) – Combining CAD function with drafting to generate the production drawings of the part for the purpose of downstream processing.  CAE (Computer Aided Engineering) – To support basic error checking, analysis, optimization, manufacturability, etc. of a product.  CAM (Computer Aided Manufacturing) – To develop the Computer Numerical Control part programs for machining and other processing applications.  CAPP (Computer Aided Process Planning) – To generate the process plans for the complete manufacturer of products and parts.  CATD (Computer Aided Tool Design) – To develop the tools for manufacturer such as jigs and fixture, dies and moulds.  CAP (Computer Aided Planning) – For the purpose of planning functions such as material requirement planning, computer aided scheduling, etc.  CAQ (Computer Aided Quality Assurance) – For the purpose assessing the inspection methods and developing quality control and assurance functions.  CAT (Computer Aided Testing) – As the software tools that can take a system through its various phases of operations and examine the response against the expected results.

7.  The complexity of design increases with the number and diversity of components in the final part.  Can be categorized into two main headings:  Product Engineering  Manufacturing Engineering  The two main categories can be further divided as shown in slide 9.  The design process refers to a well structured stages to reach the stage of actual part production as shown in slide 10.

8. Product success Product Engineering Manufacturing Engineering  Product functions  Product Specifications  Conceptual design  Ergonomics and Aesthetics  Standards  Detailed design  Product Development  Testing  Simulation  Analysis: o Strength o Kinematics o Dynamics o Heat o Flow o Design for manufacturer o Design for assembly  Drafting  Process Planning o Process sheets o Route sheets  Tooling o Cutting tools o Jigs and fixtures o Dies and molds  Manufacturing Information Generation o CNC part programs o Robot programs o Inspection programs  Production Organization o Bill of materials o Material requirement planning o Shop-floor control o Plant simulation  Marketing and Distribution o Packaging o Distribution o Marketing

9. Manufacturing Implementation Problem identification and need recognition Problem definition and conceptualization Geometric modeling and spatial analysis Engineering analysis and optimization Prototype development Manufacturing process development

10.  The starting point of design process.  Process involved in this stage is shown in Figure below. Basic questions: 5W & 1H

11.  This stage is about the clear definition of the problem and producing all possible ideas for solutions.  Process involved in this stage is shown in figure below.

13.  This stage is iteratively carried out by performing modification to the geometric model until the desired results is obtained.

14. Design concept Design for assembly Selection of materials and process for early cost estimates Best design concept Design for manufacture (DFM) Prototype Production Suggestions for simplification of product structure Suggestions for more economic materials and processes Details design for minimum manufacturing costs

15. Useful guidelines:  Use standard process and methods.  Limits the manufacturing process and experts to those available.  Reduce the variety of manufacturing process.  Use standard components in the design.  Provide liberal tolerances  reduce overall manufacturing cost  Use materials that have better manufacturability.  Minimized or avoided the secondary operations.  The design process should be commensurate with the level of production expected of the part.  Exploitation the identified special features for economic improvement.

16.  An additional physical tests on the part  the need to develop a physical model for such purpose.  Rapid prototyping (RP) – A means through which the product geometry as modelled in the earlier stages is utilised to get the physical shape of the component. Rapid Prototyping Working drawings Design refinement Test and evaluation Final hard copies of the components and assemblies  to provide information for the downstream application in the manufacturing. A careful evaluation of each feature and capability embedded in the design to be carried out but only involves minor modifications and enhancements. It may be necessary/desirable to carry out actual testing on actual parts to verify computer simulation.

17. Manufacturing Process Development Manufacturing information generation Tool design Process planning Manufacturing simulation Information requirement design Time & motion study Product plant design

18. Components in Manufacturing Process Development  Process Planning Determine exactly how a product will be made to meet the requirements specified at the most economical cost.  Tool Design Develop tooling design such as fixture, injection mould cavities, mould cores, mould bases, and other tooling.  Manufacturing Information Generation Refers to the various part programs required during the manufacturing such as CNC part programs, robot programs, and inspection programs.  Manufacturing Simulation Carry out the actual simulation of machining on the computer screen  cost and time saving.  Information Requirement Design Refers to the information pertinent to the manufacturing of the part that could be generated using the part model data such as BOM, material requirement planning, production planning, shop-floor control, and plant simulation.  Time and Motion study Optimize the product’s manufacturing cycle such as time for material handling, manufacturing, set-up the component and machine tool.  Production Plant Design The actual plant to produce the design for the production volumes.

19. Computer Aided Design (CAD)  Use of computer as a tool for all functions in design.  The functions involved:  Layout design for overall assembly  Individual component modelling  Assembly modelling  Interference and tolerance stack checking  Engineering drawings  Advantages of CAD: refer to chapter 1. Computer Aided Manufacturing (CAM)  Use of computer in manufacturing process.  CAM in mechanical engineering industries can be categorized:  Mass production, e.g., automobiles High volume production, from thousands to millions per annum. Use of special-purpose machines & transfer lines  low flexibility.  Batch production Refers to making jobs in medium lots, e.g., 100 to 1000. May not use transfer lines but may use special purpose machine.  Job-shop production Refers to the manufacture of small lots, e.g., single job  purpose of providing design, prototypes, tool making, or special purpose applications. No special-purpose machine or tooling can be economically justified  use of general purpose machines & tooling  error-prone process.  Advantages of CAM : refer to Chapter 1

20.  P.N. Rao (2010). CAD/CAM: Principles and applications (3 rd Edition). New Delhi: Tata McGraw-Hill