The use of computers in the design and manufacturing of products revolutionized industry in the last quarter of the 20th century. Although computer-aided design (CAD) and computer-aided manufacturing (CAM) are different areas of activity, they are now so closely integrated that they are often discussed together as CAD/CAM.
Computer-Aided Design
In 1950, science fiction writer Robert Heinlein had his future inventor create “Drafting Dan,” an automated draft-ing system that would enable designers to turn their ideas into manufacturing plans in a fraction of the time required for the hand preparation of schematics and parts lists. By the 1960s, engineers had developed the first computer-assisted design programs, running on terminals attached to mainframe computers.
The activity of a CAD workstation centers on the cre-ation of geometrical models (first 2D, then 3D). With the aid of models, a virtual representation of the product being designed can be built up. With its knowledge of geometrical and physical relationships, routines in the CAD system can perform not only measurement of dimensions and mass but also structural analysis. (In some cases CAD can be inter-faced with systems that provide full-blown simulation of the effects of stresses, heat, and other factors.)
The growth of desktop computing power in the 1980s and 1990s moved CAD from the mainframe to the high-end workstation (such as those built by Sun Microsystems) and even to high-end personal computers. The growing pro-cessing power also meant that the geometric models could become more sophisticated, including solid models with realistically rendered surfaces rather than just wireframes. The model of surfaces can include such factors as reflectiv-ity, friction, or even aerodynamic characteristics. In design-ing a product (or a subsystem of a product), engineers can now use simulation software to determine how well a group of parts in a complex assembly (such as a car’s steering mechanism) will perform. The ability to get detailed data in real time means that the CAD operator can work in a feed-back loop in which the design is incrementally refined until the required parameters are met.
This growing modeling capability has been combined with the use of detailed databases containing the stan-dard parts used in a particular industry or application. Libraries of templates allow the designer to “plug in” stan-dard assemblies of parts and then modify them. The data-bases can also be used with algorithms that can assist the designer in optimizing the design for some desired char-acteristic, such as strength, light weight, or lower cost. Recent systems even have the capability to set “strategic” design goals for a whole family of products and to identify particular optimizations that would help each part or sub-system achieve those goals.
Computer-aided Manufacturing
The automated fabricating of products on the factory floor originally developed independently of computer-aided design. Numerically controlled machine tools and lathes can be programmed using specialized languages such as APT (Automatically Programmed Tool) or more recently, through a system that uses a graphical interface. Advances in pattern recognition and other artificial intelligence techniques have been used to improve the ability of the automatic tool to identify particular features (such as holes into which bolts are to be inserted) and to properly orient surfaces. At some point the programmability and flexibility of the system with regard to its ability to manipulate the environment gives it the characteristics of a robot (see robotics).
Integration of CAD and CAM
As CAD systems became more capable, it soon became evi-dent that there could be substantial benefits to be gained from integrating the design and manufacturing process.
The CAD software can also output detailed parts and assembly specifications that can be fed into the CAM pro-cess. In turn, manufacturing considerations can be applied to the selection of parts during the design process.
The integration of design, simulation, and manu-facturing continues. The goal is to give the engineer a seamless way to “tweak” a design and have a number of simulation modules automatically depict the effects of the design change. In essence, the designer or engineer would be working in a virtual world that accurately reflects the physical constraints that the product will face in the real world.
The automation of the design and manufacturing process has been mainly responsible for the increasing productivity of modern factories. Factories using traditional methods in producing complex products such as automobiles or con-sumer electronics have generally had to refit for CAD/CAM in order to remain competitive. Low-skill but relatively high-paying factory jobs characteristic of the earlier industrial era have given way to smaller numbers of more technical jobs. This has meant a greater emphasis on education and special-ized training for the industrial workforce.
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