Friday, October 10, 2008

What is CAD/CAM?

What is CAD/CAM?
The term [CAD]/[CAM] is a shortening of Computer-Aided Design [CAD] and Computer-Aided Manufacturing [CAM]. The term [CAD]/NC (Numerical Control) is equivalent in some industries.

[CAD]/[CAM] software uses [CAD] drawing tools to describe geometries used by the [CAM] portion of the program to define a toolpath that will direct the motion of a machine tool to machine the exact shape that was drawn.

History
Numerically-Controlled Machines
Well before the development of Computer-aided design, the manufacturing world adopted tools controlled by numbers and letters to fill the need for manufacturing complex shapes in an accurate and repeatable manner. During the 1950's these Numerically-Controlled machines used the existing technology of paper tapes with regularly spaced holes punched in them (think of the paper roll that makes an old-fashioned player piano work, but only one inch wide) to feed numbers into controller machines that were wired to the motors positioning the work on machine tools. The electro-mechanical nature of the controllers allowed digital technologies to be easily incorporated as they were developed.

By the late 1960's Numerically-Controlled machining centers were commercially available, incorporating a variety of machining processes and automatic tool changing. Such tools were capable of doing work on multiple surfaces of a workpiece, moving the workpiece to positions programmed in advance and using a variety of tools - all automatically. What is more, the same work could be done over and over again with extraordinary precision and very little additional human input. NC tools immediately raised automation of manufacturing to a new level once feedback loops were incorporated (the tool tells the computer where it is, while the computer tells it where it should be).

What finally made NC technology enormously successful was the development of the universal NC programming language called APT (Automatically Programmed Tools). Announced at MIT in 1962, APT allowed programmers to develop postprocessors specific to each type of NC tool so that the output from the APT program could be shared among different parties with different manufacturing capabilities.

[CAD] & [CAM] Together at Last
The development of Computer-aided design had little effect on CNC initially due to the different capabilities and file formats used by drawing and machining programs. However, as [CAD] applications such as SolidWorks and Auto[CAD] incorporate [CAM] intelligence, and as [CAM] applications such as Master[CAM] adopt sophisticated [CAD] tools, both designers and manufacturers are now enjoying an increasing variety of capable [CAD]/[CAM] software. Most [CAD]/[CAM] software was developed for product development and the design and manufacturing of components and molds, but they are being used by architects with greater frequency.

Today, over three-quarters of new machine tools incorporate CNC technologies. These tools are used in every conceivable manufacturing sector, including many that affect building technologies. CNC technology is related to Computer Integrated Manufacturing (CIM), Computer Aided Process Planning (CAPP) and other technologies such as Group Technology (GT) and Cellular Manufacturing. Flexible Manufacturing Systems (FMS) and Just-In-Time Production (JIT) are made possible by Numerically-Controlled Machines. 

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