High-aspect-ratio WC-Co microstructure produced by the combination of LIGA and micro-EDM

Abstract A high-aspect-ratio WC-Co (tungsten carbide super hard alloy) microstructure has been produced by a new microfabrication process which combines LIGA and micro-EDM (electro-discharge machining). The 1 mm long microstructure with gear pattern has a variation of 4 μm in the outside diameter along its length. In the process, LIGA fabricated electrodes of negative geometry are electroplated in a metal plate for use in the micro-EDM. Since the arrangement is extremely precise the serial micro-EDM processes for one workpiece can be implemented by exchanging worn electrodes for new ones via X–Y positioning between the workpiece and each electrode. In this type of machining any bulk conductor can be chosen as the material, which is to be shaped into a microstructure. WC-Co chosen in this experiment has a much larger Young's modulus and hardness than ordinary electroplated materials. The fabricated high-aspect-ratio WC-Co microstructures can have high resistance to buckling and wear when used as mechanical components or tools.