Rehman Ata Ur, Arif Waseem, Hussain Muhammad Imtiaz, Miran Sajjad, Hussain Salman, Lee Gwi Hyun
Department of Industrial Engineering, University of Engineering & Technology Taxila, Taxila 47050, Pakistan.
Department of Mechanical Engineering, University of Gujrat, Gujrat 50700, Pakistan.
Materials (Basel). 2022 Jul 15;15(14):4932. doi: 10.3390/ma15144932.
Electric discharge machining with a powder mix dielectric is a promising technique to harden a work piece's surface using electricity with a high energy density. The quality of the electrical discharge-machined surface is related to its surface integrity in which the surface's roughness, residual stresses, micro hardness and surface micro cracks are some of the major factors. In this research, graphite powder was mixed in a dielectric with a particle size of 20 µm, 30 µm, and 40 µm, with the concentration of the graphite powder ranging from 2 g/L to 4 g/L. Moreover, the peak current and pulse time on were also coupled with an additive of graphite powder to investigate the effect on the surface quality, i.e., the recast layer thickness, micro hardness and crater depth as well as the material removal rate (MRR) and tool wear rate (TWR). A Box-Behnken design was employed to design the experiments and the experimental results revealed that the graphite powder size and concentration coupled with the electrical parameters (peak current and pulse time on) significantly influenced the recast layer thickness, micro hardness, crater size, MRR and TWR. The crater depth and micro hardness were maximized at a higher concentration and particle size, while the recast layer thickness was reduced with a higher gain size.
使用粉末混合电介质的放电加工是一种很有前景的技术，可利用高能量密度的电来硬化工件表面。放电加工表面的质量与其表面完整性相关，其中表面粗糙度、残余应力、显微硬度和表面微裂纹是一些主要因素。在本研究中，将粒径为20 µm、30 µm和40 µm的石墨粉末混入电介质中，石墨粉末的浓度范围为2 g/L至4 g/L。此外，峰值电流和脉冲开启时间也与石墨粉末添加剂相结合，以研究其对表面质量的影响，即重铸层厚度、显微硬度和凹坑深度以及材料去除率（MRR）和刀具磨损率（TWR）。采用Box-Behnken设计来设计实验，实验结果表明，石墨粉末尺寸和浓度与电参数（峰值电流和脉冲开启时间）相结合，对重铸层厚度、显微硬度、凹坑尺寸、MRR和TWR有显著影响。在较高的浓度和粒径下，凹坑深度和显微硬度达到最大值，而随着粒径增大，重铸层厚度减小。
