IJSRD - International Journal for Scientific Research & Development| Vol. 5, Issue 10, 2017 | ISSN (online): 2321-0613 All rights reserved by www.ijsrd.com 338 Comparative Study of Dielectric Fluid in Powder Mixed Electro – Discharge Machining Prof. Vaibhav V. Phule 1 Prof. Laxman P. Khose 2 1,2 Professor 1,2 Department of Mechanical Engineering 1,2 D Y Patil College of Engg. Akurdi, Pune Abstract— Electro discharge machining (EDM) is nontraditional machining process which is used to remove the material by thermal energy of the spark. All electrically conductive materials can be machined. EDM is a capable of machining hard material components or geometrically complex. As there is no direct contact between tool and work piece, no physical cutting forces are present between tool and workpiece. In recent years to enhance process capabilities, powder mixed electric discharge machining (PMEDM) is used as new technique. In PMEDM dielectric fluid is mixed with additive powder. For Experimentation parameters selected are peak current, pulse on time, duty cycle and different dielectric media. Material removal rate, tool wear rate and surface roughness are taken as the output parameter. Key words: PMEDM, Material removal rate, Surface roughness, Tool Wear Rate I. INTRODUCTION In PMEDM process, a suitable material in fine powder form (Aluminum, Chromium, Graphite, Copper, Silicon Carbide, etc.) is mixed into the dielectric fluid of EDM. Additive powder particles fill the spark gap (Fig. 1). The performance of EDM process is significantly affected by addition of powder. The electrically conductive powder particle reduces the insulating strength of the dielectric fluid and increases the spark gap distance between the tool electrode and workpiece. This results as stable process, thereby improving material romoval rate (MRR) and surface Roughness (SR). II. EXPERIMENTAL SETUP PM-EDM setup is used and experiments are carried on EDM (Fig. 2.). Design of experiments is done by using Taguchi technique. Mild Steel of 2 mm thick is used as a work piece material. Copper electrode with a diameter of 6 mm is used as tool electrode. The machining is performed in standard Kerosene. Fig. 1: Principle of PMEDM Process [3] Silicon Carbide ( SiC), Graphite and Aluminium oxide (Al2O3) powder is mixed in Kerosene(Ker) as per the requirements of the experiments. The powder particle size of 15 microns and powder concentration of 50 gm/litre is used. Experiments are performed on Sumedha EDM machine. The experimental layout for the machining parameters using the L12 orthogonal array is used. This array consists of four parameters and three levels Level Current (A) POT (μsec) Duty cycle (%) Dielectric fluid 1 5 5 90 Silicon Carbide(SiC) 2 10 10 85 Graphite 3 15 30 80 Aluminum Oxide (Al2O3) Table 1: Process Parameters and their Levels for Trial Experiments Ex p. No . Dielectri c media Curr ent (A) PO T (μs ec) Du ty cyc le (% ) MRR (gm/ min) TWR (gm/ min) SR (μ m) 1 Ker 5 5 90 0.013 4 0.000 5 4.7 3 2 Ker 10 10 85 0.069 8 0.001 8 6.7 0 3 Ker 15 30 80 0.085 3 0.003 7 8.5 0 4 Ker+ SiC 5 5 90 0.029 6 0.000 6 2.6 4 5 Ker+ SiC 10 10 85 0.077 7 0.002 8 5.1 1 6 Ker + SiC 15 30 80 0.098 2 0.005 7 6.7 7 7 Ker+Gra phite 5 5 90 0.040 2 0.000 9 3.8 3 8 Ker+Gra phite 10 10 85 0.089 6 0.006 9 6.2 1 9 Ker+Gra phite 15 30 80 0.125 0 0.009 0 7.9 3 10 Ker + Al2O3 5 5 90 0.033 7 0.000 8 3.2 11 Ker + Al2O3 10 10 85 0.081 2 0.004 9 5.8 1 12 Ker + Al2O3 15 30 80 0.108 5 0.008 7 7.6 Table 2: Results of Experiments MRR and TWR are calculated by the following equations: MRR = Wwͳ − Wwʹ T ሺͳሻ TWR = Wtͳ − Wtʹ T ሺʹሻ Where Ww1= weight of work piece before machining (gm) Ww2= weight of work piece after machining (gm)