Fabrication of mass micro-holes using the hybrid precision extruded-wax electroforming and micro-EDM processes

A hybrid process combined precision extruded-wax electroforming with micro-EDM for 100 micro-holes mass production is implemented in this study. It can produce mass micro-holes of 126 μm in average diameter in a cost-effective batch way. First, EDM peck-drilling is adopted to perforate a substrate of SUS304 plate with micro through-holes. Two miniature devices including an extrusion die and a deposition mould for electroforming are then designed and implemented. The temperature of the oily wax, serving as an excellent sacrificial material, is carefully controlled to obtain an array of precise micro pillars. Then, a precision electroforming of thick nickel metal-layer onto the substrate is involved. The wax mould is then completely removed by heated 70°C of water to reveal the final product-a perforated mass micro-holes array of nickel with 150mm thick. Experimental results show that the finished mass micro-holes have uniform diameters and precise cylindrical periphery without taper and burrs. It is expected the proposed approach contributes significantly to the mass production processes of micro precision holes with a cost effective way.