Magnetic Bearing Spindles for Enhancing Tool Path Accuracy.

Thin rib machining of electronic components or airframe structures can beneflt from high speed machining for burr free cuttlag, improved surface quality and increased metal removal rate. It is suggested that the use of a magnetic bearing spindle can not only successfully provide the beneflts of high speed machining but, more importantly, minimize tool path errors. In this paper the various sources of tool path errors are discussed as functions of machine tool positioning errors and cutting force errors which are characterized as static, dynamic and stochastic. The operation of high speed magnetic bearing spindles is described and a control scheme whereby the spindle may be translated and tilted for minimizing tool path errors is discussed. This overall research activity is a cooperative effort between The University of Maryland, Cincinnati Milacron, and The National Bureau of Standards