1. Option E – Computer Aided Design, Manufacture and Production This option is concerned with understanding how computer based technologies have transformed the nature of the design and manufacture of products. It considers the impact of the application of such technologies on the role of the designer and manufacturer and the associated implications for the consumer. The development of CAD/CAM has radically changed production processes causing a fundamental rethink in the relationship between designer, manufacturer and consumer.

2. The Impact of CAD on the Design Process There are a huge range of programs available that come under the broad umbrella of CAD. There are also a range of common applications that can be used to assist in the design process.

3. Describe a suitable design situation for each of the following types of software application: –Drawing Package (eg Techsoft 2D Design, AutoCAD) –Graphics Package (eg CorelDraw, Adobe Illustrator) –Modelling Package (eg Pro/Desktop, RhinoSoft) –Structural Design Package –Architectural Design Package –Spreadsheet (Microsoft Excel, Lotus 123) –Word Processing (Microsoft Word, Lotus WordPro) –Presentation Package (Microsoft Powerpoint) –Desktop Publisher (Microsoft Publisher) –Internet Browser (Internet Explorer)

4. Computer Modelling Which of the previous list of software packages can be used for modelling? How would a designer select the most appropriate piece of software for a particular task?

5. Animation versus Virtual Reality Animation – The ability to link graphic screens together in such a way as to simulate motion or a process. The ability to simulate a real situation on the screen and interact with it in a near natural way. Where and why would you use animation techniques as opposed to virtual reality techniques? What are the relative advantages and disadvantages of each? How does the use of animation and virtual reality techniques help conserve resources?

10. Computer Input Devices Several devices can be used to input data to a CAD System. Explain a possible use for each of these: –Scanner –Digital Camera –Graphics Tablet –Video Camera –Keyboard –Mouse –Tracker Ball

11. Computer Output Devices Several devices can be used to output data from a CAD System. Explain a possible use for each of these: –Printer –Plotter –CNC Machine

12. The Impact of CAD/CAM on Manufacturing How does a numerically controlled (NC) machine aid manufacturing? Think about quality of reproduction, reduction in the need for skilled operators and speed of manufacturing. Consider, specifically, the difference in manufacturing a chess piece by hand and by CNC production.

13. The difference between Automatic machines and CNC Machines. Prior to the advent of modern CNC machining techniques, automated manufacture was done either by mechanically controlled machines or by punched tape and card machines. Mechanically controlled machines required on very precisely set levers, cams, pulleys and gears to govern the motion of the tools against the material. Punched tape machines made use of a series of digital numbers, stored as holes on a roll or paper tape, and a punched tape reader to control the position and movement of the tools. Both systems required very careful programming and setting up and were largely inflexible. Modern CNC techniques offer far greater flexibility, reprogrammability and multi-machine integration and control.

14. CAD/CAM Links CAD Packages such as Techsoft 2-D Design and Pro/Desktop are vector drawing programs. This means that all of the marks on the screen are interpreted as mathematical formulae. This is different to paint packages which produce bitmaps where the information is stored as 3 number co-ordinates itentifying the specific “bit” on the screen as XY with a third number identifying the “colour”. In a CAD/CAM system, the vector drawing information is translated into a series of movements between co-ordinates that the tools must follow.

15. Example We will now watch the simulation of the program which machines the Namecard holder shown below. While watching it, take note of the program that is scrolling in the top half of the screen, the program is made up of a series of columns.

16. Example

17. G & M Codes These columns give specific numerical information to the machine. For example, N indicates the line number of the program, G is a General code and describes the type of machining operation (eg Rapid Traverse, Clockwise Circular etc.), X Y & Z give 3-dimensional coordinates that the tool needs to move to and so on. The nest slides shows the G & M codes used by Boxford programs, we’ll then work through the first 10 lines of the program.

19. Manufacture of Namecard Holder We’ll now manufacture a Namecard holder each. While operating the Boxford Duets notice that the computer requires a machine interface which in this case if the blue box located under the monitors. This box is the “brains” of the CNC machine and is what translates the numerical data from the computer into movement of the tools. Also notice that you need to identify the material type to be manufactured and that this allows the interface to feedback machining information to the computer.

20. CNC Machines The are a huge range of CNC Machines available: 1.Sewing machines 2.Knitting machines 3.Lathes 4.Milling machines 5.Routers 6.Shaping machines 7.Engravers 8.Plotters 9.Rapid Prototyping 10.Laser Cutters

24. Computer Integrated Manufacture Computer Integrated Manufacture (CIM) is the total integration of the various individual CAD, CNC, robotics, computer-aided process planning, computer- aided quality control and materials handling systems. In a fully developed CIM system a CAD system will be networked with computer controlled manufacturing systems which might include CNC machines, robots and materials handling component. All components of the system will share the same database and have instant access to it. This allows a central controller to manage all aspects of the manufacture of products and for design changes to be incorporated very quickly.

25. CIM Advantages –More choice, can design-in own requirements, more consistent quality, cheaper products, parts easily manufactured and changed, random introduction of parts, less lead time, less labour and waste, best machine utilisation, improvements in productivity and quality control, greater consistency, fewer errors and waste, high quality of finish. Disadvantages –High initial investment and personnel, training costs, job losses, lack of individuality. More definitions