Hideaki Onozuka

Ultra-Precision Cutting of Roll Die with Micro Lens Arrays for Plastic Film

Patterning vast numbers of micro lenses on a surface increases technical importance to improve characteristics of optical parts such as liquid crystal displays. A cutting method using a diamond tool is examined to make a molding die by which array patterns of many micro lenses are molded. Realizing the cutting procedure, the developed machining system employs a cutting unit actuated by PZT and a synchronous control system of the cutting unit with a NC controller. The present paper investigates machining of micro lenses on the order of 2 kHz, using a piezo-actuated micro cutting unit. Experiments using this unit revealed that it is possible to machine a large number of micro lenses on a molding roll die for plastic film with high precision.

Study on Machining Vibration Suppression with Multiple Tuned Mass Dampers: Vibration Control for Long Fin Machining

This study aims to suppress vibration during the machining of long and thin fin parts. Typically, fin parts have low stiffness because fixing the fin is impeded by a end-mill, machine tool or other fins. In this study, multiple tuned mass dampers (TMDs) with the same characteristics were applied to the machining of a fin part measuring 18 mm × 180 mm × 2600 mm. The characteristics of the TMDs were optimized by calculation using a lumped-mass-points system model of the fin part. Then, an impact hammer test and a machining test were conducted on the actual fin part. The dynamic stiffness of the fin part was improved by up to 14 times by using five TMDs, and the amplitude of vibration during machining was decreased by more than 90%.