Journal of Materials Research and Technology (Jul 2020)
Comprehensive analysis of material removal rate, tool wear and surface roughness in electrical discharge turning of L2 tool steel
Abstract
Electrical discharge turning (EDT) is used in the production of micro and macro cylindrical components with complex geometry, as well as ejector pins in injection molds, components of micro air turbines and pumps, micro tools or microstamping dies. On the other hand, optimization of machining parameters is crucial for machining efficiency and surface integrity of a part produced directly by EDT. Therefore, the machinability of AISI L2 steel with die-sinking EDT was comprehensively investigated by considering material removal rate (MRR), surface roughness (Ra) and tool wear rate (TWR). In addition, machining parameters named as discharge current, pulse on time and pulse off time were optimized by Taguchi-based grey relational analysis method. Considering the measurement results and the observations of surface morphology, the MRR, TWR and Ra increased with increasing the discharge current. However, it was detected that MRR and Ra increased while TWR decreased as the pulse on time was increased. The increase in noncutting time due to the pulse off time increment led to forming of shallow craters and thus increased surface quality. The best machining parameters for die-sinking EDT of the tool steel were determined as discharge current of 3A, pulse on time of 8 μs and pulse off time of 6 μs. A 25.04% percentage of improvement of was achieved with the multiresponse optimization method during die-sinking EDT.
