Modelling and optimisation of electro-discharge diamond face grinding of cemented carbide-cobalt composite

摘要

Electro-discharge diamond grinding is a hybrid process of electro-discharge machining (EDM) and diamond grinding which is obtained by replacing the tool electrode of conventional EDM by a metal bonded diamond wheel. When face of the wheel is used for machining then the process is termed as electro-discharge diamond face grinding (EDDFG). In this study, modelling and optimisation of EDDFG of cemented carbide-cobalt composite has been done using a hybrid methodology comprising of Taguchi methodology (TM) and response surface methodology (RSM) with material removal rate (MRR), wheel wear rate (WWR) and average surface roughness (ASR) as the objective functions. The approach first uses the TM for finding the optimum level of input machining parameters such as wheel speed, current, pulse on-time and duty factor. The optimum input parameter values are further used as the central values in the RSM to develop second-order response model for MRR, WWR and ASR after conducting experiments using central composite rotatable design matrix. The simultaneous optimisation of weighted response has been obtained using MINITAB software. The results show considerable improvement in three quality characteristics when the hybrid approach is used, as compared with the results of only a TM approach.