Precision Polishing of Micro Mold by Using Piezoelectric Actuator Incorporated with Mechanical Amplitude Magnified Mechanism
Demands of precision molds with complicated microstructures for digital devices such as DVD pick-up system, medical devices such as μ-TAS and solar optics etc. are increasing [1 - 5]. The structured molds must be polished after grinding or cutting in order to improve the surface roughness. In this paper, a two dimensional low frequency vibration (2DLFV) polishing actuator using PZT is proposed and developed. The 2DLFV consists of 4 mechanical amplitude magnified actuators (MechaTrans), a multilayer 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 multilayer stacked piezoelectric actuator around 7 times to 120 μm. With this actuation, the tool vibrates in a circle trajectory to achieve polishing effect. In the polishing experiments, tungsten carbide molds (workpieces) are polished with diamond slurry. The surface roughness of the work pieces and polishing efficiency are evaluated. From the experimental results, it was found that low frequency vibration especially 2DLFV is a useful polishing system for micro structured mold.
S. K. Chee et al., "Precision Polishing of Micro Mold by Using Piezoelectric Actuator Incorporated with Mechanical Amplitude Magnified Mechanism", Advanced Materials Research, Vol. 325, pp. 470-475, 2011