A novel spark erosion technique for the fabrication of high aspect ratio micro-grooves

Micro groove is an important geometrical feature of components used in microsystem technology (MST). Straight micro grooves are the predominant features in microsystem components such as micro heat exchangers and diffraction gratings. Micro Electrical Discharge Machining (micro EDM) is a complementary microfabrication technique adopted from the conventional EDM machining process for the purpose of micro machining. Using micro EDM it is possible to machine all electrically conductive materials irrespective of their hardness. High aspect ratio microgroove machining for length as high as 20 mm is a formidable task for the conventional micro EDM. In the present work, a novel spark erosion technique has been described wherein a graphite foil has been used instead of the traditional pin shaped tool electrode, for the purpose of making straight grooves. In a single setup microgroove of 20 mm length and an aspect ratio of about 2.3 has been achieved on hardened tool steel by this technique. This process is further refined by using the gravitational effect for the effective debris removal, which has improved the aspect ratio to about 8.

[1]  P. Dario,et al.  Non-traditional technologies for microfabrication , 1995 .

[2]  Masanori Kunieda,et al.  Improvement of EDM efficiency of silicon single crystal through ohmic contact , 2000 .

[3]  M. Pollnau.  Broadband luminescent materials in waveguide geometry , 2003 .

[4]  J. S. Soni,et al.  Experimental investigation on migration of material during EDM of die steel (T215 Cr12) , 1996 .

[5]  S. H. Lee,et al.  Study of the effect of machining parameters on the machining characteristics in electrical discharge machining of tungsten carbide , 2001 .

[6]  G. L. Benavides,et al.  High aspect ratio meso-scale parts enabled by wire micro-EDM , 2002 .

[7]  Y. Wong,et al.  Effect of TiC in copper–tungsten electrodes on EDM performance , 2001 .

[8]  M. Benzohra,et al.  Using microchannels to cool microprocessors: a transmission-line-matrix study , 2003, Microelectron. J..

[9]  Fritz B. Prinz,et al.  Electro-discharge machining of mesoscopic parts with electroplated copper and hot-pressed silver tungsten electrodes , 2000 .

[10]  Kamlakar P Rajurkar,et al.  Formation and Ejection of EDM Debris , 1985 .

[11]  B. Yan,et al.  Study of added powder in kerosene for the micro-slit machining of titanium alloy using electro-discharge machining , 2000 .

[12]  Inseob Song,et al.  Fabrication of a microchannel integrated with inner sensors and the analysis of its laminar flow characteristics , 2003 .

[13]  J. McGeough,et al.  Micromachining of Engineering Materials , 2001 .

[14]  Robert O. Warrington,et al.  The miniaturization technologies: past, present, and future , 1995, IEEE Trans. Ind. Electron..

[15]  Huiying Wu,et al.  An experimental study of convective heat transfer in silicon microchannels with different surface conditions , 2003 .

[16]  B. Yan,et al.  Micro slit machining using electro-discharge machining with a modified rotary disk electrode (RDE) , 1999 .

[17]  Mukund R. Patel,et al.  Theoretical models of the electrical discharge machining process. I. A simple cathode erosion model , 1989 .