Design Components of Manufacturing

1. Design Components of Manufacturing

2. Computer-aided Design – CAD • New parts or alterations to existing parts are designed by means of computer • Definition:- the application of computers and graphics software to aid or enhance product design from conceptualization to documentation • many organizations, CAD is usually introduced as a separate entity

3. CIM integrates together CAD and all other databases for the organization • Basic CAD system would consist of: • input devices - e.g keyboard, mouse • processing and storage - CPU, storage devices • output devices - monitor, plotter

4. Hardware - used to develop, store and display the geometrical part shapes • Object stored as geometric and graphical parameters for lines, arcs and curves • When object is loaded in the computer’s active memory for display it is put in a bitmap, but can be stored in vector format - regenerated to bitmaps for display • Display is by turning on Picture Elemnts (pixels) on the monitor.

5. Software: • Two broad categories - 2D and 3D • Numerous software available commercially - e.g. AutoCAD, Pro/ENGINEER, CATIA, I-Deas • CAD software will normally translate data for/from different file formats and inputs - i.e. systems linked through CAE so that different applications can share information in the database

6. Because of the diversity in the various CAD platforms, a need for exchange of data exists - Initial Graphics Exchange Specification (IGES) format allows for this. Types of CAD Hardware: • Mainframes: • powerful, multiple program execution, good support and response for large drawings and designs • large initial cost, requires large number of users to maintain low cost per terminal, complex OS, single failure can terminates all work

7. RISC platforms (workstations) • lower cost, good performance ratio, multiple program execution • requires multiple copies of CAD software, UNIX rather complex • PC platforms • cheap, simple OS • more difficult to integrate into CIM, lower capability, cannot support complex or multiple designs easily.

8. The CAD process involves a) Geometric Modeling - description of a physical object or part mathematically. Models can be represented in 2D (as lines) or in 3D (lines, wire frames, surfaces or solids) b) Design Analysis and optimization – performing an engineering analysis such as FEA on the model. Experiments may be required (see chap. 5) c) Design Review and evaluation d) Documentation and drafting – hard copies, specifications, coding

9. CAD model representations

10. Current trends in CAD involve • workgroups in which different groups concurrently design different aspects of the product while sharing the data in real time – Concurrent or Simultaneous engineering (Example – Airbus Consortium) • product development management; applications involving the Internet; CIM applications.

11. Type and complexity of drawings involved degree of axysymmetry, curved surfaces, interior complexity, parts in assembly Concept vs Repetitive Design for repetitive 2D often sufficient; concept might require more modelling Size and complexity of product Selection of CAD hardware and software - considerations

12. Enterprise Data Interfaces • data available for product brochures and manuals easily, ease of CNC code generation, ease of PPC • External Data Interface • electronic data interchange(EDI), type EDI between contractor and vendor, transferrability of data

13. Concurrent Engineering

14. Production Engineering

15. Production Engineering • Process Planning • CAPP • Production machine programming • CAM • Tool/Fixture engineering • Work/Production standards • Time/motion study

16. Production Engineering • Plant engineering • DFMA • Manufacturing cost estimating.

17. Product Data Management • Also known as PLM • PDM organizes and supports shared database • Functions • Store CAD data • Control master BOM – relational database • Conversion of CAD data to other formats