Manufacturing Technology Today

M. Chellamalai ¹, Gowtham Hegde ², V. R. Raju ¹

Affiliations
1 Ultra Precision Engineering Department, Central Manufacturing Technology Institute (CMTI), Tumkur Road, Bangalore, IN
2 National Institute of Technology Karnataka, Surathkal, IN

Abstract

The micro electro discharge machining process, the erosive action of an electrical discharge between electrode and workpiece is used to remove material. Electro-thermal erosion creates small craters both in the workpiece and the tool during machining progress, with this technique excessive electrode wear leads to increased gap size between the tool and workpiece results inconsistent performance. Understanding the electrode wear and influencing factors are crucial to more accurate and reliable micro EDM process. This paper presents an electrode wear of different electrode material such as Copper, Copper-Tungsten, Brass, and Graphite at different micro EDM parameters were analyzed. The objective of this study is to know the electrode wear and surface roughness of the different electrode material, in the micro EDM machining process. The effect of electrode wear rate (EWR) and surface roughness (R_a) has been investigated for Stainless Steel work piece material and the different electrodes such as Copper, Brass, Copper-Tungsten, Graphite. The shape of the different electrodes is ball nose type. Experiments were repeated for different gap voltage values and the different electrode materials. Micro EDM machine Model DT-110 is used for the experimentation. The work materials which are difficult to machine like heat treated tool steels, composites, super alloys, and ceramics can be easily machined in μEDM process. This study investigates the results of a various experimental parameters such as voltage, capacitance on material removal rate, electrode wear rate and surface quality of Stainless Steel 304 in the micro EDM process.

Keywords

Micro EDM, Surface Roughness, Electrode Wear Rate, Micro Machining.

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V. R. Raju ¹, C. K. Srinivasa ¹, A. R. Vinod ¹, M. Chellamalai ¹, P. V. Shashikumar ¹

Affiliations
1 Central Manufacturing Technology Institute, Tumkur Road, Bangalore, IN

Abstract

Electrical Discharge Machining (EDM) is one of the non-conventional machining processes used for machining of electrically conductive materials. Mechanism of material removal in EDM is based on conversion of electrical energy into thermal energy. In this paper, copper electrodes of diameter 0.1, 0.4 and 0.8 mm were used for machining holes on steel work-piece to a depth of 0.2 mm by micro-EDM process. Experiments were conducted at a capacitance of 0.001, 0.01, 0.1 and 0.4 μF with a gap voltage of 80 V and the electrode was rotated at 100 rpm during ED machining. Wear on the electrode; surface roughness and the size of the machined hole were measured. Capacitance had a profound influence on the material removal rate, volumetric wear ratio, spark gap and surface roughness of work-piece.

Keywords

EDM, Micro-Holes, Electrodes, Wear, Capacitance, Spark Gap.

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