TABLE OF CONTENTS The relationships between various reference points in CNC programming are expressed as preset numeric values. More often than not, these numbers, these specific values, are required well before the actual machine setup takes place. During part programming, many dimensions are known exactly, others are known approximately and there are also many that are not known at all. Some known dimensions are subject to variations between jobs. Without any corrective facility available to the programmer, it will be almost impossible to setup the machine precisely and efficiently. Fortunately, modern controls offer many features to make both programming and machine setup an easier, faster and more precise activity. A number of coordinate systems, offsets and compensations are typical support tools used in programming for corrective purposes.
One of the oldest programming techniques available in programming is called a position compensation. As the name suggests, using position compensation functions, the actual tool position is compensated relative to its theoretical or assumed position.
It is only one of several corrective methods available to the programmer and machine operator. On modern CNC systems, this method is still available for compatibility with older programs. Today, this technique is not really needed. It has been replaced by the much more flexible Work Offsets (Work Coordinate System), described in the next chapter of this handbook. The current chapter describes some typical programming applications that can benefit from using the old-fashioned position compensation method.
The main purpose of position compensation is...
