Micro-hole machining using micro-EDM combined with electropolishing

This paper presents a novel process of using micro-electro-discharge- machining (micro-EDM) combined with electropolishing to improve the surface roughness of micro-holes. During the machining process, a tool is fabricated by wire electro-discharge grinding (WEDG) directly by using micro-EDM for machining the micro-hole and by electropolishing to finish the hole wall. In this work, various micro-holes are machined on the high nickel alloy. By the electropolishing method, high surface quality of the hole wall is obtained by applying a suitable electrolytic voltage and an appropriate concentration of electrolyte in about 5 min of machining time. The taper and burrs of the inlet of holes are reduced, even for difficult- to-machine special-shaped micro-holes. The surface roughness reduced from 2.11 µm Rmax before grinding to 0.69 µm Rmax after electropolishing.

[1]  Kamlakar P Rajurkar,et al.  3D Micro-EDM Using CAD/CAM , 2000 .

[2]  Shi Hyoung Ryu,et al.  Electro-chemical micro drilling using ultra short pulses , 2004 .

[3]  C. Sutcliffe,et al.  Analysis of laser micro drilled holes through aluminium for micro-manufacturing applications , 2005 .

[4]  Biing-Hwa Yan,et al.  Application of micro-EDM combined with high-frequency dither grinding to micro-hole machining , 2006 .

[5]  Dominiek Reynaerts,et al.  Microstructuring of silicon by electro-discharge machining (EDM) — part I: theory , 1996 .

[6]  Hong Hocheng,et al.  Electropolishing and electrobrightening of holes using different feeding electrodes , 1999 .

[7]  Stephen T. Newman,et al.  State of the art electrical discharge machining (EDM) , 2003 .

[8]  Liam Blunt,et al.  3D surface characterisation of electropolished EDMed surface and quantitative assessment of process variables using Taguchi Methodology , 2002 .

[9]  Mahmudur Rahman,et al.  A study on the machining of high-aspect ratio micro-structures using micro-EDM , 2003 .

[10]  Takahisa Masuzawa,et al.  Wire Electro-Discharge Grinding for Micro-Machining , 1985 .

[11]  Takahisa Masuzawa,et al.  A Combined Electrical Machining Process for Micronozzle Fabrication , 1994 .

[12]  T. Masuzawa,et al.  Micro-EDM for Three-Dimensional Cavities - Development of Uniform Wear Method - , 1998 .

[13]  S. Rhim,et al.  Micro-hole fabrication by mechanical punching process , 2005 .

[14]  P. Jacquet.  Electrolytic Method for obtaining Bright Copper Surfaces , 1935, Nature.

[15]  B. Yan,et al.  Use of micro ultrasonic vibration lapping to enhance the precision of microholes drilled by micro electro-discharge machining , 2002 .