Abstract
Powder Mixed Electrical Discharge Machining (PMEDM) is considered as one of the viable methods to machine the materials which are hard and tough but with appreciable thermo-electrical properties. In PMEDM, it has been established that machinability is enhanced by adding additives in the form of fine powders in the spark gap of EDM process. In this investigation, the role of the thermo-electrical properties of workpiece on PMEDM process has been studied. Materials with distinct thermoelectric property, namely Mild Steel and Aluminium are taken as workpiece with Alumina as additive powder for the PMEDM process. Experiments have been conducted with Taguchi L9 Orthogonal Array (OA) with Material Removal Rate (MRR) and Tool Wear Index (TWI) as responses. Gap current, duty cycle and flow rate of powder mixed dielectric liquid have been taken as process parameters at 3 levels with circular copper rod of 12 mm diameter as tool electrode. Determination of the influence of properties of the workpiece on the machinability has been performed using a custom made PMEDM set-up. ANOVA and main effect plot of data means for the aforementioned conditions have been analysed. The results are noteworthy with significant influence of the properties of the workpiece on the machinability of PMEDM process.
Highlights
Electrical discharge machining (EDM), called as spark erosion technique, is one of the feasible manufacturing techniques used to machine the materials which are hard and tough to be manufactured in the conventional machining process
The study attempted to assess the effect of the material property of the workpiece in the machinability in Powder mixed EDM (PMEDM) process
There occurs significant rise in the Material Removal Rate (MRR) of PMEDM with Aluminium than in the MRR of the PMEDM with Mild Steel workpiece. 17.52% is the maximum rise in the MRR of Aluminium – PMEDM combination with minimum rise of MRR as 4.1%
Summary
Electrical discharge machining (EDM), called as spark erosion technique, is one of the feasible manufacturing techniques used to machine the materials which are hard and tough to be manufactured in the conventional machining process. The process time involved in EDM is so longer that it makes the machining very slower Over these years, researchers made several attempts to achieve satisfactory machining rate in EDM and subsequently the following variants of EDM comes into exists viz., dry EDM, EDM with ultrasonic vibration, Powder mixed EDM (PMEDM), EDM in water etc., [4]. Researchers made several attempts to achieve satisfactory machining rate in EDM and subsequently the following variants of EDM comes into exists viz., dry EDM, EDM with ultrasonic vibration, Powder mixed EDM (PMEDM), EDM in water etc., [4] In all these processes, EDM is basically involved together with a newer mechanism to enhance the machining rate of the EDM process. It was reported that the phenomenon of the occurrence of earlier spark in PMEDM resulted in the machining of materials at lower gap voltage, thereby enhancing the material removal rate and tool wear index [13, 14]
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