Machining Process Acceptability for High Performance Materials by Multiple Sensor Monitoring

The principal roadblocks to the industrial implementation of NiTi alloy products are given by the difficulties in their manufacturing processes. Very high deformation at failure, severe strain hardening and unique pseudoelastic behavior make NiTi alloy machining properties quite complex, yielding problems in material processing and workpiece quality. Following the call for a deeper insight into the machinability of NiTi alloys, a collaborative research work was carried out by two Laboratories: the Machining Technology Laboratory at the Fraunhofer Institute for Machine Tools and Forming Technology (IWU), Chemnitz, Germany, and the Laboratory for Advanced Production Technology (LAPT) at the Department of Materials and Production Engineering, University of Naples Federico II, Italy. The joint research activities comprised cutting force and acceleration sensor monitoring during turning of NiTi alloy under different cutting conditions. The main scope was to correlate sensorial data and process acceptability for machinability assessment through a supervised expert knowledge based neural network paradigm. In this paper, a particular focus is dedicated to sensor fusion of signal data for the integration of information generated by sensors of different nature in order to better and more robustly characterize NiTi alloy machining process conditions.