The application of piezo based subsystems for improved machining processes

Due to their very high applicable forces, frequencies and their stiffness, piezoceramics are feasible to serve as integrated actuators in machines. The application of piezo based components in production engineering was subject of plenty of investigations in the past. That focuses primarily on systems for condition monitoring, structural vibration reduction or chatter prevention. However there are currently also few approaches that aim to use piezo actuators for directly induced vibrations for improved machining processes. In this paper we present an overview of such systems, their parameters and the technological background. Known approaches will be classified and divided into groups considering their working principles, actuator performance and application technology. Ultra sonic machining (USM) for example is a comparatively old approach which applies ultrasonic vibrations of a sonotrode to an abrasive slurry for machining hard, brittle and nonconductive material. Vibration assisted machining (VAM) systems are rather different. They are characterized by low stroke, uncontrolled but highly frequent resonant vibrations of the tool to achieve enhanced chipping behavior or generally enable to machine certain hard materials. Fast Tool servo (FTS) systems are even more complex. They apply an overlaid controlled movement of the cutting edge to manufacture microstructures or possess to manufacture complex geometries like non circular bores or turned parts. Selected systems will be presented in detail showing their design approach, actuator parameters, control considerations and measurement data of manufactured parts. These will be for instance an ultrasonic deep hole drilling tool, a form honing system, an active spindle mounting for micro contouring and a piezo based machine table for manufacturing non circular bores in small workpieces. Summarized the existing systems will be compared considering their advantages and eventual hindrances. Beyond that the outlook will show problems, which need to be solved in the future to enable piezo assisted machining systems a more comprehensive application in manufacturing