Comparison of Micro-milling and Micro-EDM Operations

The production of micro-parts often involves micro-milling and micro-EDM operations. Although both processes are competitive for certain geometries, each of both processes has its specific advantages. Driven by the current trend of hybridization of machining processes it is important to know which process or which combination of processes to use in order to attain a certain performance level. Therefore this paper compares micro-milling and micro-EDM operations specifically for the machining of rectangular shaped geometries. The comparison is based on several performance parameters like dimensional and geometrical accuracy, surface roughness, machining time and energy consumption. This initial study shows that for the considered geometries a comparable dimensional accuracy can be obtained for both processes. Besides this it is shown that micro-milling excels micro-EDM in terms of flatness of the bottom surface, surface roughness and machining time. On the contrary, micro-EDM gives better performance in terms of straightness of the walls and energy consumption. Based on these results combined machining strategies are proposed which make use of the advantages of both processes.