小形金型貫通穴の超音波振動による研磨(工具と工作物間の相対運動による研磨領域の拡大)

Lapping experiment for finishing inside surface of a through hole opened in a metal-mold material by WEDM was carried out. Ultrasonic vibration was given to a resin lapping tool which was formed around the middle part of a vibration rod. To expand the lapping area, a relative spiral motion was newly applied in this experiment between the resin tool and the metal mold. The effects of the mesh number(#1500, #3000, #8000) of WA abrasive in slurry and the normal lapping force(1 N, 2N, 3N, 4N, 5N) onto the characteristics of surface roughness and lapping uniformity were elucidated. The obtained results are summarised as follows. (1) The relationship between the lapping process time and the surface roughness was almost linear on the log-log graph. (2) The highest improvement rate of surface roughness in this experiment was obtained under the condition of mesh number #1500 and lapping force 5N, and then the surface roughness of Ra 0.08 μm was obtained after the lapping process time of 120 min. (3) It is expected that much smaller surface roughness can be obtained if much greater lapping force was applied. (4) Relatively high lapping uniformity was obtained under the condition of mesh number # 1500 and lapping force 5N though the uniformity was lower under the condition of the larger mesh number and the smaller lapping force