Optimization of machining parameters during cryogenic turning of AISI D3 steel

This research paper depicts the process of used liquid nitrogen at the interface of TiN coated carbide cutting tool insert (rake face) and AISI D3 workpiece. Design of experiments (DoE) was planned according to Taguchi L-9 (OA) orthogonal array. The experimental results during machining such as cutting force, machining time and temperature were optimized by Taguchi S/N ratio and analysed by ANOVA. The contribution of machining parameters of (i) speed, (ii) feed and (iii) depth of cut for each response were evaluated. Feed had the highest effect on the percentage of contribution of 57.21% and 52.21% for cutting force and machining time, respectively. Speed had the highest effect on the contribution as 79.57% for the temperature at the interface of insert and workpiece. The predicted values at the optimum level of machining parameters for cutting force, machining time and temperature were 44.49 N, 37.09 sec. and 24.99 degrees C, respectively. Regression models were made. The R-Sq values were 96.59, 89.34 and 96.09% for cutting force, machining time and temperature, respectively. The ratio of an average thickness of generated chip and feed was considered as the chip compression ratio. It was observed that the generated chips during cryogenic turning were thin, discontinuous, long snarled and most of the material had side flow on either side.