In the present research, similar and dissimilar resistance spot welding (RSW) process of St12 and galvanized steel sheets with thickness of 0.9 mm was investigated. The experiments were carried out based on the statistical design of experiments (DOE) approach to investigate the effect of RSW parameters on the welding quality, achieving the mathematical regression equations and predicting the new results. Welding time and electrode force were considered as the input process variables while the tensile-shear strength of the joints was considered as the process response. By comparing three RSW types, galvanized steel has the highest tensile-shear strength. Statistical analysis shows that tensile-shear strength is increased with increasing electrode force and welding time. Verification experiments for three types of RSW joints were carried out in order to analyse the obtained results via software. Good agreement between the verification tests and the optimization results revealed that the statistical modelling would be appropriate for RSW process. Welding time (T)  = 5 s and electrode force (P)  = 925 N, welding time (T) = 5 s and electrode force (P) = 1100 N and welding time (T) = 3 s and electrode force (P) = 925 N were obtained as the optimum settings for similar RSW of St12, dissimilar RSW of St12 to galvanized steel and similar RSW of galvanized steel, respectively. Manuscript profile

In this study EDM milling process parameters of AISI H13, have been investigated by using Response Surface Methodology (RSM). Current (16-32A), pulse-on time (100-700 µs) and depth of cut (1-3mm) were considered as independent variables, while surface roughness, tool wear ratio (TWR), and material removal rate (MRR) as process output responses. Results reveal that increases in the current and decreases in pulse-on time cause more MRR and more TWR and depth of cutting has no significant effect on them. Minimum surface roughness, minimum TWR and maximum MRR were considered as optimization criteria. Verification experiments were carried out in order to analyze the results via software. Optimized settings were used for EDM Milling and die sink EDM experiments to compare the results. The results indicate that using EDM milling has considerable economic savings than die sink EDM, better surface roughness, and higher MRR. Manuscript profile