Computer-Aided Design (CAD) and Computer-Aided Manufacturing (CAM).
CAM systems are associated with computer numerical control (CNC) or direct numerical control (DNC) systems. Since both CAD and CAM use computer-based methods for encoding geometrical data, it is possible for the processes of design and manufacture to be highly integrated.
CAD had its origins in three separate sources, which also serve to highlight the basic operations that CAD systems provide. The second source of CAD was in the testing of designs by simulation. The third source of CAD development resulted from efforts to facilitate the flow from the design process to the manufacturing process using numerical control (NC) technologies, which enjoyed widespread use in many applications by the mid-1960s.
In addition to parts-shaping by traditional machine tool processes such as stamping, drilling, milling, and grinding, CAD/CAM has come to be used by firms involved in producing consumer electronics, electronic components, molded plastics, and a host of other products. Computers are also used to control a number of manufacturing processes (such as chemical processing) that are not strictly defined as CAM because the control data are not based on geometrical parameters.
Using CAD, it is possible to simulate in three dimensions the movement of a part through a production process. The continuing development of the simulation of various manufacturing processes is one of the key means by which CAD and CAM systems are becoming increasingly integrated.
ADVANTAGES AND DISADVANTAGES. Autodesk
Modeling with CAD systems offers a number of advantages over traditional drafting methods that use squares, rulers, and compasses. CAD systems also lend themselves to modeling cutaway drawings, in which the internal shape of a part is revealed, and to illustrating the spatial relationships among a system of parts.
To understand CAD it is also useful to understand what CAD can not do. CAD systems have no means of comprehending real-world concepts, such as the nature of the object being designed or the function that object will serve.
Other limitations to CAD are being addressed by research and development in the field of expert systems. One example of an expert system involves incorporating information about the nature of materials– their weight, tensile strength, flexibility, and so on– into CAD software. By including this and other information, the CAD system could then “know” what an expert engineer knows when that engineer creates a design.
One of the key areas of development in CAD technologies is the simulation of performance. Among the most common types of simulation are testing for response to stress and modeling the process by which a part might be manufactured or the dynamic relationships among a system of parts. The ease with which a part’s specifications can be changed facilitates the development of optimal dynamic efficiencies, both as regards the functioning of a system of parts and the manufacture of any given part.
The processes of design and manufacture are, in some sense, conceptually separable. The design process must be undertaken with an understanding of the nature of the production process. It is necessary, for example, for a designer to know the properties of the materials with which the part might be built, the various techniques by which the part might be shaped, and the scale of production that is economically viable. The conceptual overlap between design and manufacture is suggestive of the potential benefits of CAD and CAM and the reason they are generally considered together as a system.