Study on precision polishing of micro structured mold

Development of micro polishing system using piezoelectric actuator incorporated with mechanical transformer

Abstract

Demands of precision molds with complicated microstructures for digital devices, μ-TAS and etc. are increasing ^[1]. The structured molds must be polished after grinding or cutting in order to improve the surface roughness. In this report, a two dimensional low frequency vibration (2DLFV) polishing actuator using PZT is proposed and developed. The 2DLFV consists of 4 MechaTrans, a multiplayer stacked piezoelectric actuator (PZT) incorporated with mechanical transformer, and a center piece. Mechanical transformer is a kind of flexure hinges structured that magnifies the stroke of the multiplayer stacked piezoelectric actuator around 7 times to 120 μm. With this actuation, the tool vibrates in a circle trajectory to achieve polishing effect ^[2]. In the polishing experiments, tungsten carbide molds (work pieces) are polished with diamond slurry. The surface roughness of the work pieces and polishing efficiency are evaluated. From the experimental results, we found low frequency vibration especially 2DLFV is a useful micro polishing system for micro structured mold.