Multiobjective process optimisation for turning of tool steels

A simple methodology for an effective multiobjective process optimisation of machining conditions of multipass lathe operation is developed. The approach integrates the Principal Component Analysis (PCA) and Taguchi methods to optimise the Computerised Numerical Control (CNC) turning process. The targeted Multiple Quality Characteristics (MQCs) are the Dimensional Precision (DP), accuracy and Surface Roughness (SR) of the machined products. Eight control factors such as coolant, cutting speed, feed, depth of cut, coating type, chipbreaker geometry, nose radius and shape of the insert arranged in a L18 orthogonal array are investigated using the Taguchi method. According to the PCA of the experimental results, the verification test of the optimal process conditions shows that the optimal conditions successfully produce the best results on the DP and accuracy and SR. The optimal solution obtained can also be conveniently implemented in the part programmes of a CNC lathe. It is believed that such work can provide a wider acceptance and more practical application of machining economics in industry.