An experimental and comparative study on rough and trim cutting operation in WEDM of hard to machine materials

摘要

In present work, an experimental study of rough and trim cutting operation in wire electrical discharge machining (WEDM) has been presented on four hard to machine materials namely WC-Co composite, HCHCr steel alloy, Nimonic-90 and Monel-400." Machining speed and surface characteristics were the major performance characteristics in WEDM process. Investigation shows that in rough cutting operation, machining speed and surface roughness increases with increasing discharge energy across the electrodes. Different values of machining speed and surface roughness were obtained for four work materials under the similar conditions of discharge energy .Due to the different values of thermal conductivity, melting and boiling temperatures, depth and size of surface craters on machined surface vary for each work material. Trim cutting operation at similar discharge parameters but with different wire offset were performed for four work materials. Micro-hardness profiles underneath the machined surface after rough and trim cutting operation were observed.Result shows that using single trim cutting operation with appropriate wire offset, surface characteristics can be improved irrespective of the rough cutting operation.