Takayuki Nakagawa

Development of a 5-DOF Controlled, Wide-Bandwidth, High-Precision Maglev Actuator for Micro Electrical Discharge Machining

This paper describes a five degrees of freedom (5-DOF) controlled, wide-bandwidth, high-precision maglev local actuator to maintain a suitable distance between an electrode and the workpiece for micro electrical discharge machining (EDM). The actuator is sufficiently compact to be attached to conventional electrical discharge machines. The maglev actuator possesses a positioning resolution of the order of sub-micrometer and micro-radian, a bandwidth greater than 100 Hz in the 5-DOF directions, and a positioning stroke of 2 mm in the thrust direction. The maglev actuator can be levitated stably and positioned precisely, even under electrical discharge conditions. The use of the maglev actuator could increase the machining speed for Phi 1 mm holes by 21.8%, compared with the conventional EDM.

High-Speed and High-Accuracy EDM of Micro Holes by Using a 5-DOF Controlled Maglev Local Actuator

The objective of this study is to realize high-speed and high-accuracy electrical discharge machining (EDM) of micro holes using a combination of a conventional EDM machine and a maglev local actuator. In this paper, the conventional EDM machine and the wide-bandwidth, high-precision, 5-DOF controlled maglev local actuator are combined and cooperatively controlled. Then to accelerate the debris ejection from the machined holes, the driving methods of the axial jump and radial vibration of the electrode are discussed. The experimental results show that the maglev local actuator can adjust the gap between the electrode and a workpiece speedily, and the machining speed is improved by 434.2%, compared with conventional EDM machine. Moreover, by the jump and the circular motion of the electrode, the debris ejection can be accelerated, the abnormal electrical discharge can be avoided, and the machining speed also is improved by 580.3%.