Influence of ZnO nanoparticle addition and spark peak current on EDM process of AISI 1045, AISI 4140, and AISI D3: MRR, surface roughness, and surface topography

In this paper, the performance of ZnO nanoparticles (as a nanoparticle with low thermal and high electrical resistance) and current peak on improving material removal rate (MRR), surface roughness, and the tribology properties (including wear rate and friction coefficient) of the manufactured surface is evaluated. The studies of the tribology properties reveal the performance of ZnO nanoparticle coated on the surface by the plasma channel temperature in the EDM process. For this purpose, the effects of the peak current (6, 12, 18, and 24A) and ZnO particle mass (1, 2, 3, and 4 g), and thermal conductivity of AISI1045, AISI4140, and AISID3 on MRR, surface roughness are investigated. The results illustrate that in the condition with 4 g of the ZnO nanoparticle mass and peak current 18A, the MRR increases up to 10.71%, 33.33%, and 45.55%, for rough machining of AISI1045, AISI4140, and AISID3, respectively. It seems that in this condition, the appropriate thermal balance between the nano-dielectric and thermal conductivity of steels is provided, which can improve the machinability. Finish machining with 6A for peak current and 1, 2, 3, and 4 g of nanoparticle was done. Although in all of the experiments (except for AISID3 with 4 g) the MRR are reduced, the surface roughness improvements as much as 16.66%, 29.41%, and 56.25% are occurred in 2 g, 3 g, and 3 g of AISI1045, AISI4140, and AISID3, respectively. Also, the pin-on-disc experiment results indicate that the best improvement of the tribology characteristic can be achieved with 3 g of ZnO that decreases the friction coefficient as much as 55.1%, 65.42%, and 79.85% in AISI1045, AISI4140, and AISID3, respectively.