Servo piezo tool SPT400MML for the fast and precise machining of free forms

Abstract

Recent requirements for accuracy and resolution demand higher quality in the machining of precision parts in many industries—such as optics, automotive and aerospace—by free form machining. The required operations are possible by using expensive manufacturing equipment in parallel with several processes such as grinding and polishing. By using a new fast tool servo, the so-called servo piezo tool SPT400MML, driven by a piezoelectric actuator for the precision diamond turning of non-symmetrical surfaces, components can be machined with a fast motion control of the tool (diamond or carbide). The SPT400MML embeds a patented amplified piezoelectric actuator APA400MML and a real-time controller based on a FPGA component able to improve the overall accuracy. Models based on mechanical FEM software and control design software are used to optimise the achieved performances. Experiments have been undertaken to show the capability to displace a diamond tool on a 400-µm stroke with a first resonant frequency of above 600 Hz.