外文翻译--CADCAM.docVIP

CAD/CAM Computer technology has risen in an exponential curve. Only a generation ago computers were not really needed for NC control. Except for relatively few five-axis machines. NC was point to point, which was easily accomplished with manual programming. With the advent of two-dimensional profiling, hower, a need arose for numerous calculations to generate the curved profile. At that point the computer was looked upon as a useful tool in manufacturing engineering. After some development, it was found that punched or magnetic tape could be dispensed with entirely in favor of computer programs that controlled the machines directly. Then came the minicomputers, which when operating with the central processor brought about the first real concept of the automatic factory. All of these developments were important steps in the advance of technology. The computer is no longer viewed as a remote piece of hardware used primarily in accounting and engineering departments, but instead as an important tool to be used increasingly in CAD and CAM. Today CAD and CAM have become closely linked for complete processing from design to production. The desin engineer can now create the desired design on a CRT screen that is linked to a computerized graphics plotter. The same system can be used to determine the viability of the design by analyzing stresses and deflections that will take place under loading conditions. The functioning of mechanical linkages may also be checked. After the design is complete, the production group can draw on the information developed in CAD for computer-aided manufacture. Thus the unified CAD-CAM team has been developed to bring the product from the design concept through manufacture. CAD Functions Initially CAD systems were primarily automated drafting stations in which computer plotters produced engineering drawings. The systems were later linked to graphic display terminals, which allowed the user to communicate with the computer in pictures inste