Fabrication of Electroplated Cu Tool Electrodes for Micro-EDM using a Si Micromold

摘要

Micro Electro Discharge Machining (Micro-EDM) provides a potential for the fabrication of micro cavities in materials independently of their respective hardness. Such cavities may serve many purposes, like lubrication grooves in the tool industry to name just one example. To match the desired application, specific types and shapes of tool electrodes are required. Using Si structures as patterns for a micro electroplating process, truncated and non-truncated pyramid shaped microelectrodes may be fabricated with high precision. Si is a well-understood wafer material for the fabrication of Micro Electro-mechanical Systems (MEMS). Pyramid shaped grooves can be created in the surface of single crystalline Si due to the material's anisotropic etching properties. Using KOH as a wet chemical etching agent, Si will form wall shapes and angles, which are dependent on the crystallographic orientation of the Si. For the fabrication of pyramid electrodes, Si (100) was used providing a wall angle of 54.7° after wet chemical etching. For these experiments, Cu was used as tool electrode material for EDM. Cu electrodes fabricated for Micro-EDM featured a tool wear comparable to the one of a conventional Cu wire electrode.