Electroplastic cutting influence in machining processes

Resumen

The thesis presented is performed with the aim of studying the effect of electropulses (EPs) in machining processes such as drilling and round turning processes for different materials. When the EPs of short duration are applied to metals undergoing plastic deformation, the deformation resistance decreases and plasticity increases at the same time. The influence of EPs on the plastic flow is called electroplastic effect. Chip formation during machining is greatly influenced by cutting speed, feed rates and tool geometry. Selecting properly these parameters for a particular machining operation is very important to achieve high machining efficiency. It was found that EPs assisted cutting processes improve the machinability of materials based on the electroplastic effect. The influence of EPs in drilling process is studied by combining different feed rates, drill diameters and current densities in aluminium 7075 and steel 1045. Similarly, the effect of electropulsing has been observed for aluminium 6060 and steel S235 during turning process. The correlation between chip compression ratio , shear plane angle f , cutting speed, feed rates and current densities have been studied in EPs assisted processes. It has been observed that lower feed rates and subsequently, high current densities reduce the shear angle f and increase the chip compression ratio during drilling process. The specific cutting energy (SCE) is reduced upto 27% in aluminium 7075 and 17% in steel 1045 when drilling is assisted with EPs. However, the chip compression ratio decreases and shear plane angle f increases with the increase in cutting speed during turning of steel S235. In contrast, chip compression ratio increases and shear plane angle decreases with the increase in cutting speed while turning of aluminium 6060. The current density decreases with the increase in feed rates and increases with the increase in cutting speed in steel S235. However, current density has high values at higher feed rates and it decreases with the increase in cutting speed during turning of aluminium 6060. The SCE decreased with the increase in feed rates and depth of cut during electrically assisted turning of steel S235. But for aluminium 6060, the SCE increased whenthe cutting speed is increased. The results elaborated that electrically assisted drilling process improves the material machinability by decreasing SCE in aluminium 7075 and steel 1045. The electrically assisted turning process seems to have influence in improving the machinability of steel S235 but for aluminium 6060, the plastic deformation tends to be increased by increasing the SCE during EPs assisted turning process.