Fabrication of Different Micro Patterned Arrays by Through Mask Electrochemical Micromachining

Abstract

Patterned microstructures are among the basic micro features that are indispensable in improving the tribological performance and dependability of various mechanical components especially Micro-Electro-Mechanical Systems (MEMS). Through Mask Electrochemical Micromachining (TMEMM) is a feasible process for fabricating micro-patterned arrays with controlled dimension, location and density by maintaining suitable surface texture. In this paper, appropriate machining parameters along with optimal electrolyte combination have been utilized for achieving patterned arrays in the form of micro-dimples and micro-square features. Low aspect ratio mask made of a negative PR (AZ 4903) is being introduced during TMEMM due to its low cost, availability and chemical resistance. Pattern of micro-holes with an average diameter of 65μm as well as micro-squares with a side length of 65μm imprinted on the mask are being replicated over SS304 substrate with substantial repeatability. The influence of two major Electrochemical Micromachining (EMM) parameters viz. duty cycle and machining time are investigated on the machining accuracy and surface properties of the micro-dimples generated with mask of lean thicknesses. Circular micro-dimples with an undercut of 29.15μm, depth 44.10μm and Ra 0.091μm and square micro-dimples possessing 32.63μm undercut, 40.24μm depth and 0.081μm Ra have been successfully fabricated on SS304 by this process of TMEMM.