CNC, Computer Numerical Control

CNC (Computer Numeric Control) indicates that a machine performs its movements controlled by a computer. The computer controls position and movement of a certain number of axes, e.g. three axes called X, Y and Z, in a CNC cutter. In addition, the computer also controls a number of other things e.g. the motors (the speed) and the water used for cooling. Everything is controlled by so-called “G-codes” and a command line is a code or a code followed by one or more numbers or letters.

A command line for a cutter is for example:
G00 X100 Z00 (Go to position X=100 in quick motion)
G01 X150 Z100 S1000 F50 (Go to position X=150 Z=100 with a rotary speed of 1000 n/min and a tension level of 50 mm/min).

Previously, i.e. 20 – 25 years ago, the command lines were entered one at a time but nowadays encoding is typically done by a computer program. The computer program, a so-called CAM program, reads the file with the drawings and automatically converts it to G-codes. The CAM program is often an integral part of the actual machine tool (dialogue control) or more often the program is operated from an independent computer, a powerful PC.

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