In the fabrications of the next generation inkjet nozzle and optical fiber connector with higher precision than the present one (±0.5μm), the development of high precision mold by WC-Co submicro-grained hardmetal is strongly demanded, because the hardmetal has higher wear resistance, higher fracture strength, etc., together with high rigidity. We are trying to establish the manufacturing technology of such molds with precision of ±0.3μm (the interim goal) and ±0.1μm (the final goal) by using micro-electric discharge machining and centerless grinding.
The surface roughness of rectangular alloy body that was electric discharge machined and than lapped became finer with decreasing WC grain size from ±2.5μm to ±0.5μm.
In the jogging processing by centerless grinding machining of core pin with three-stepped diameters of φ250, 125 and 80μm, the accuracy of ±0.15μm exceeding the interim goal was achieved for submaicro-grained hardmetal with ±0.5μm.