Batch mode micro-EDM for high-density and high-throughput micromachining

This paper examines scaling issues for electrode arrays used in micro-electro-discharge machining (micro-EDM). In particular, it explores constraints in the fabrication and usage of high aspect ratio LIGA-fabricated electrode arrays, as well as the limits imposed by the pulse discharge circuits on machining rates. A LIGA-fabricated array of 400 Cu electrodes with 20 /spl square/m diameter was used to machine through-holes in 50 /spl square/m thick stainless steel. An array of multi-layer structures that included tapered shapes was fabricated by the sequential use of three electrode arrays of varying shape. The electrode fabrication and usage for these efforts are described. With respect to the pulse discharge circuits, it is shown that the machining time can be reduced by >50% by dividing the electrode array into sections have independent control of pulse discharge timing. This is implemented by using individual RC timing circuits for each section. A correlation between electrode area per RC circuit and machining rate is described.