TABLE OF CONTENTS A CNC machine tool does not always cut material and 'make' chips. From the moment the cutting tool becomes active in a part program, it goes through a number of motions - some are productive (cutting), others are nonproductive (positioning).
Positioning motions are necessary but nonproductive. Unfortunately, these motions cannot be totally eliminated and have to be managed as efficiently as possible. For this purpose, the CNC system provides a feature called the rapid traverse motion. Its main objective is to shorten the positioning time between non-cutting operations, where the cutting tool is not in contact with the part. Rapid motion operations usually involve four types of motion:
From the tool change position towards the part
From the part towards the tool change position
Motions to bypass obstacles
Motions between different positions on the part
Rapid traverse motion, sometimes called a positioning motion, is a method of moving the cutting tool from one position to another position at a rapid rate of the machine. The maximum rapid rate is determined by CNC machine manufacturer and takes place within the machine travel limits.
The common rapid rate for many larger CNC machines is about 25000 mm/min (985 in/min). Medium and smaller machines can go much higher, offering rapid motion up to 75000 mm/min (2950 in/min) or even more, particularly for smaller machines. Machine manufacturer determines the rate of rapid motion for each of the machine axes. The motion rate can be the same for...
