Study of Machining Accuracy of Micro Punching Mold Using Micro-EDM

Abstract

As one of the micro-forming technologies, micro punching process produces workpieces in high efficiency and low cost. It has attracted the attention of researchers from all over the world in recent years. The current micro punching mold is prepared on-line by micro electrical discharge machining (EDM) with simple cross-sectional shape. During punching, the punching load is small due to the soft material and small circumference of workpiece. To form micro part with complex cross sectional shape using micro punching technology, three-dimensional micro-EDM milling and reversed micro EDM are used to generate micro die and punch on-line to provide a solution to alignment of die and punch on machine. In order to obtain high dimensional accuracy of micro punching mold, in this paper, dimensional errors including electrode, reversed electrode, micro die and micro punch caused during machining process are identified. The correlation between dimensional errors and the clearance of micro die and micro punch are analyzed. Based on preliminary experimental results and dimensional error control strategy, the final punching clearance of micro punch molds was machined within the required range.