Numerical Control Programming
Chapter 1
What Is Numerical Control & What Does It Do?


The programming process can be considerably simplified and speeded up (particularly for complex geometry workpieces) by using a computer routine to assist the N/C programmer. Before the advent of the affordable, PC-based engineering workstation with interactive CAD and CAM software applications, CNC programmers had to either manually hand-code each command or use some sort of computer-based code generator. The two most widely used text-based computer routines--or languages--were COMPACT II and APT. Although these routines were not difficult to learn to use, they were primarily text-based and required the programmer to develop programs in a non-interactive mode. The same program could be used on a wide variety of N/C machines, simply by changing one or two statements.

With the coming of ever more powerful microcomputer hardware and software and the pardigm-changing graphical user interface (GUI)--commonly known as either the Macintosh and Windows interface (depending upon which side of the ideological fence one is on)--developed by XEROX Palo Alto Research Center (PARC), the use of text-based NC programming systems such as COMPACT II and APT fell quickly aside. Why? The GUI-base CAM systems made CNC path development more automated, more intuitive, more interactive, more efficient, and more productive. Time is money; saving time means either less cost, more profit...or both.

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What Comprises an N/C System?

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Updated Jan. 9, 2002
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