TABLE OF CONTENTS During typical everyday program development, the number of tool length offsets in a program will correspond to the number of different tools used in the same program. Normally, each tool requires and uses only a single length offset. It is also typical, that the tool number and the offset number are the same, for a logical association during setup: T01 will be associated with H01, T16 with H16, etc. In some cases, the CNC programmer will benefit from programming two (or even more) tool length offsets for a single tool. Also, there are other methods available that achieve the same goal, so consider the methods and techniques described in this chapter as several different options.
The concept of programming tool length should be familiar to all programmers and operators. In its simplest form, tool length offset is the measured distance from a tool reference point (command point) to part reference point (Z0). In reality, it is not a measurement of an actual tool, but its distance only. This method is the most popular, particularly in small shops and job jobs, as it does not require any special setup equipment. Another method, commonly used in high production environment, uses a special tool presetter that allows tool length (and other tool data) to be set off-machine. For the purposes of this chapter, no setup equipment is needed, and the tool setup will use the common touch-off method, measured from the bottom of the tool cutting edge to Z0...
