Applicability of Diatomite Powder-Mixed Dielectric Fluid in Electrical Discharge Machining Processes

Electrical Discharge Machining (EDM) is a well-esta blished non- contact machining technique for manufacturing geome trically complex shapes on hard but electrically conductive materials that are extremely difficult-to- cut by conventional processes. EDM has low material removal rate and Powder-Mixed Electrical Discharge Machining (PMEDM) is one of the latest techniques that has emerged to improve material rem oval rate and electrode wear ratio among other performance characteristics. However, its utilization in the manufacturing industry is very low because m any fundamental issues of this new development are not well understood. In th is study, the performance of the PMEDM process was evaluated in terms of Mate rial Removal Rate (MRR) and Electrode Wear Ratio (EWR) with respect t o peak current and pulse-on time. Experiments were carried out at a du ty cycle of 0.5, peak current of 21A and pulse frequency of 10 KHz. Peak current and pulse-on time were varied from 3-21A and 45 - 135µs, respect ively for pure (distilled water) and distilled water suspended with diatomite (powder-mixed dielectric fluid) at a concentration of 2 g/l. Graphite tool e lectrode was used to machine mild steel workpiece submerged in dielectric fluid. Each of the experimental set was conducted for 10 minutes and analysis of va riances on MRR and EWR were performed using Statistical Analysis of System (SAS) software at 5% level of significance. Completely randomized design was used to plan and analyze the experiments which were performed on Too lcraft A25 sinker electrical discharge machine with retrofitted diele ctric fluid circulation system. This study has found that variations of pea k current and pulse-on time in diatomite powder-mixed dielectric fluid have sig nificant influence on