Feed-drive system with a permanent magnet linear motor for ultra precision machine tools

High- and ultra-precision cutting of nonferrous and ferrous materials call for high performance feed drive and guidance systems to obtain excellent smooth surfaces. Usually, spindle nut systems and rotating servo motors are provided as feed drives. Nonlinearities, such as friction and micro backlash, show negative effects on the surface quality. Linear motor direct drives, however, yield better results using a new transistor converter with high resolution PWM and synchronized current measurement with oversampling techniques. The investigations have shown that this drive system is well suited for ultraprecision machines