Modeling of Melt-Pool Formation and Material Removal in Micro-Electrodischarge Machining

This paper presents a micro-electrodischarge machining (EDM) melt-pool model to predict workpiece (anode) material removal from a single discharge micro-EDM process. To model the melt-pool, heat transfer and fluid flow equations are solved in the domain containing dielectric and workpiece material. A level set method is used to identify solid and liquid fractions of the workpiece material when the material is molten by micro-EDM plasma heat flux. The plasma heat flux, plasma pressure and the radius of the plasma bubble have been estimated by a micro-EDM plasma model and serve as inputs to the melt-pool model to predict the volume of material removed from the surface of the workpiece. Experiments are carried out to study the effect of interelectrode voltage and gap distance on the crater size. For interelectrode voltage in the range of 200–300 V and gap distance of 1,2 μm, the model predicts crater diameter in the range of 78–96 μm and maximum crater depth of 8–9 μm for discharge duration of 2 μs. The crater diameter values for most of experimental craters show good agreement with the simulated crater shapes. However, the model over-predicts the crater depths compared to the experiments.

[1]  Shiv Gopal Kapoor,et al.  A Model of Micro Electro-Discharge Machining Plasma Discharge in Deionized Water , 2014 .

[2]  Todd Palmer,et al.  Heat transfer and fluid flow during keyhole mode laser welding of tantalum, Ti–6Al–4V, 304L stainless steel and vanadium , 2007 .

[3]  G. Boothroyd,et al.  Fundamentals of machining and machine tools , 2006 .

[4]  Hai-Lung Tsai,et al.  Weld Pool Dynamics and the Formation of Ripples in 3D Gas Metal Arc Welding , 2008 .

[5]  Rishi Singal,et al.  Fundamentals of Machining and Machine Tools , 2008 .

[6]  Ajit Singh,et al.  A thermo-electric model of material removal during electric discharge machining , 1999 .

[7]  S. Müller,et al.  Marangoni Convection during Free Electron Laser Nitriding of Titanium , 2009 .

[8]  A. Lichtenberg,et al.  Principles of Plasma Discharges and Materials Processing , 1994 .

[9]  Masanori Kunieda,et al.  Advancing EDM through fundamental insight into the process , 2005 .

[10]  S. S. Pande,et al.  Thermo-physical modeling of die-sinking EDM process , 2010 .

[11]  H. Tsai,et al.  Modeling Three-Dimensional Plasma Arc in Gas Tungsten Arc Welding , 2012 .

[12]  A. Shih,et al.  Modeling of the Anode Crater Formation in Electrical Discharge Machining , 2012 .

[13]  S. Yeo,et al.  Critical assessment and numerical comparison of electro-thermal models in EDM , 2008 .

[14]  Kenneth G. Heinz Fundamental study of magnetic field-assisted micro-EDM for non-magnetic materials , 2010 .

[15]  T. Govindan,et al.  Modeling of electron cyclotron resonance discharges , 1995 .

[16]  Richard E. DeVor,et al.  An investigation of magnetic-field-assisted material removal in micro-EDM for nonmagnetic materials , 2011 .

[17]  Mukund R. Patel,et al.  Theoretical models of the electrical discharge machining process. II. The anode erosion model , 1989 .