Electrochemical Spark Micromachining Process

Abstract

Electrochemical spark micromachining process (ECSMM) is a process suitable for micromachining of electrically non-conducting materials. Besides the classic semiconductor technology, there are various methods and processes for micromachining such as Reactive Ion Etching (RIE) (Rodriguez et al., 2003), femto-second pulse laser radiation (Hantovsky et al., 2006), chemical etching and plasma-enhanced chemical vapor deposition (Claire, 2004)], spark assisted chemical engraving (Fasico and Wuthrich, 2004) and micro-stereolithography (Rajaraman, 2006) in practice. Use of photoresist as sacrificial layer to realize micro-channels in micro fluidic systems is discussed in (Coraci, 2005). All these methods are expensive as they need the vacuum, clean environment and mostly involve in between multi processing steps to arrive at the final microchannel machining results. There is a need of an innovative process which is cost effective and straight forward without employing intermediate processing steps. One such process thought of and being researched is electrochemical spark micromachining (ECSMM) process. The ECSMM process is a stand alone process unlike others and it does not demand on intermediate processing steps such as: masking, pattern transfer, passivation, sample preparation etc. The use of separate coolants is also not required in performing the micromachining by ECSMM. Micromachining needs are forcing reconsideration of electrochemical techniques as a viable solution (Marc Madau, 1997). Another similar process termed as spark assisted chemical engraving (SACE) (Wuthrich et al., 1999) has been employed for the micromachining of glass. ECSMM is a strong candidate for microfabrication utilizing the best of electrochemical machining (ECM) and electro discharge machining (EDM) together. Applications of ECS for microfabrication can be in the field of aeronautics, mechanical, electrical engineering and similar others. It can successfully process silicon (Kulkarni et. al., 2010a), molybdenum (Kulkarni et. al., 2011c), tantalum (Kulkarni et. al., 2011a), quartz (Deepshikha, 2007; Kulkarni et. al., 2011a), glass ((Kulkarni et al., 2011a, 2011b); Wuthrich et al. 1999)), alumina (Jain et al., 1999), advanced ceramics (Sorkhel et al., 1996) and many other materials. The chapter discusses the details of the experimental set-up developed in the next section. The procedure for micromachining using the developed set-up is outlined next. The experimental scheme to perform machining on glass pellets (cover slips used in biological applications) is presented. Discussion of the micro machined samples is presented. This discussion is based on various on line and post process measurements performed. The qualitative material removal mechanism is presented based on the results and discussions.