Electrochemical micro machining characteristics of Fe₆₄Ni₃₆ invar film using micro WC rod electrode

Abstract

The need for products containing micro-features has shown a remarkably and steady growth in many fields of application in recent years. For the development of micro-feature devices, one of the most important technologies is ECMM (ElectroChemical Micro Machining). In numerous non-conventional micro machining, ECMM has merits such as leaving no residual stress and lower surface roughness on machined products and also it is the absence of heat-affected zone around the cutting area. ECMM is one of the most appropriate machining method for Invar alloy micro machining, and little research has focused on the micro groove machining on Invar film. In this paper, the machining characteristics of ECMM for Invar thin film with WC rod electrode is investigated. By controlling applied voltage, machining time and pulse condition, the machined area and depth of groove on Invar film can be controlled. These methods can machine micro groove on thin Invar film, which is very difficult to do by conventional machining method, because the Invar film thickness is only 30 µm. With the increase of applied voltage and machining time, the machined depth and range of machined area became larger. Experimental results show that 60 % duty factor value is suitable for satisfying both machining rate and accuracy. And the surface quality characteristics of the machined area are investigated. For fabrication precise surface Invar film or Invar devices, high frequency condition is essential. The purpose of this study was to confirm possibilities of making grooving pattern on thin Invar film in micro size and cutting invar thin film using ECMM.