Development of high speed machine tool spindle using active magnetic bearings and application to high speed milling

Abstract

Precise exterior molds for cellular phones are usually processed by small diameter endmills. Processing time by them with diameter of less than 2 mm occupies more than 90 % machining time. In order to decrease the processing time and obtain smoothness of the surface, we have developed a machine tool spindle using active magnetic bearings, which has maximum rotational speed of 80,000 rpm. In this paper, we introduce one of new suppressing methods for spindle vibration on processing and automatic tool changing methods for magnetic bearings. Applying them to the mold processing, we verified the availability of the designed machine tool spindle.