Machining, Measurement, and Control Laboratory

A study on the tuning of CNC parameters to improve contour precision for NC Machine Tools
Yasuhiko SUZUKI (Yamazaki Mazak Corp.)
Atsushi MATSUBARA (Kyoto University)
Yoshiaki KAKINO (Kyoto University)
Soichi IBARAKI (Kyoto University)
Kangkyu LEE (Kyoto University)

This paper deals with a practical servo tuning method for high speed and high acceleration feed drives in the latest NC machine tools. CNC-servo systems in machine tool drives generally have current-velocity-position feedback controls, a feedforward controller and a command generator. Techonological progress in hardware and software makes it possible to implement a high response servo control for commercial feed drives. When feed drives are built in a complicated structure, however, vibration problems tend to occur in practical applications. Particularly vibrations at low frequencies deteriorate the contouring accuracy. In order to search the most adequate combination of CNC-servo parameters, a quick and accurate tuning method is required. This paper proposes a systematic tuning method based on simulation and measurement technology. The effectiveness of the proposed tuning method is validated by a case study involving a commercial machining center.

Key words: feed drive system, high speed machine tools, tuning, vibration, CNC servo system