The present work has been focused on cutting force (Fc) and analysis of machined surface in turning of AA 6061 alloy with uncoated and PVD‐TiB₂ coated cutting inserts. Turning tests have been conducted on a CNC turning under dry cutting conditions based on Taguchi L₁₈ (2¹ × 3³) array. Kistler 9257A type dynamometer and equipment have been used in measuring the main cutting force (Fc) in turning experiments. Analysis of variance (ANOVA) has been applied to define the effect levels of the turning parameters on Fc and Ra. Moreover, the mathematical models for Fc and Ra have been developed via linear and quadratic regression models. The results indicated that the best performance in terms of Fc and Ra was obtained at an uncoated insert, cutting speed of 350 m/min, feed rate of 0.1 mm/rev, and depth of cut of 1 mm. Moreover, the feed rate is the most influential parameter on Ra and Fc, with 64.28% and 54.9%, respectively. The developed mathematical models for cutting force (Fc) and surface roughness (Ra) present reliable results with coefficients of determination (R²) of 96.04% and 92.15%, respectively.

This work focuses on developing the mathematical model of surface roughness (Ra) in the turning of Inconel 625 superalloy with cryogenically treated tungsten carbide inserts. The influence of cryogenic treated on the microstructure and hardness of tungsten carbide tools was also investigated for the as-received inserts and deep cryogenic treatment at − 196 °C for 12, 24, and 36 h conditions. Turning experiments have been performed according to an orthogonal array L16 with three parameters (cutting tool, feed rate, cutting speed) at different levels with a 1 mm depth of cut. The ideal cutting tool and cutting parameters were evaluated in terms of the surface roughness (Ra). Analysis of Variance has been applied to determine the percentage of each cutting factor. It has been observed that the cutting speed has a maximum with 66.28% contribution on Ra. The best optimal turning parameters are obtained as A3B3C1 according to S/N ration. The mathematical model of Ra has been developed by regression analysis. The developed model is tested with verification experiments and found to be in good agreement with the experimental results.

The present work focusses on the electrical discharge machining (EDM) of Monel K 500 super alloy with different electrodes. The study’s objective is to examine the effects of process parameters and electrode materials (Cu, W-Cu, and graphite) in terms of surface quality, material removal rateand electrode wear. In this context, EDM experiments have been designed and performed using the L27 standard orthogonal array of the Taguchi method with a statistical approach. The outcomes of this study reveal that the current plays an important role to improve the EDM machining performance of Monel K 500. The surface quality is approximately 11.62% and 55.52%, respectively better when Monel K-500 alloy is machined with copper electrodes compared to those in W-Cu and graphite electrodes. Moreover, The W-Cu electrode’s wear is approximately 15.73% and 21.05%, respectively less than those of graphite and Cu electrodes in optimum processing conditions. Graphite electrodes are better than Cu and W-Cu electrodes in terms of material removal rate. The statistical results also show that the estimation equations developed to select the optimum production conditions to give high accuracy results.