In-process evaluation of tool wear effects on surface roughness variation in hard turning

Intense international and domestic economic competition has focused the attention of manufacturers on automation and flexible manufacturing as a means of increasing the productivity and the quality of manufactured products. This trend toward automation has created a need in industry for a comprehensive approach to product quality. To successfully realize full automation in machining, devices to continuously and reliably monitor the machining process are needed. These devices will allow quality assurance to be merged with manufacturing processes with the goal of approaching zero defect production. One of the crucial elements in achieving full automation in machining is a robust and accurate in-process sensor suitable for monitoring a product's surface finish. The final purpose of this research is to develop an algorithm of on-line evaluation of surface profiles of the axial sections of workpiece during hard turning operation.;In order to fulfill this purpose, computer based simulation models of tool wear and surface roughness generation during hard turning were proposed and verified through experiments using AISI M2 high speed steel of over Rc 60 and ceramic inserts without using coolants. The results showed that relative cutting vibrations were correlated with tool wear and cutting force variations. The surface roughness variation is also affected by the relative cutting vibration between tool and workpiece. Therefore, the relative cutting vibration signal was the crucial component in estimating tool wear, cutting force variations, and surface roughness generation. The research provided the feasibility to monitor surface profile generation as well as tool wear regularly in real time during a hard turning operation.