Automatic process parameter adaption for a hybrid workpiece during cylindrical operations

The combination of different materials in one workpiece in order to optimize the workpiece characteristics is a state of the art design method for high-performance components. These workpieces can be made of the most qualified materials according to local requirements. However, during machining of material compounds, the different materials have to be considered. This is due to the specific material properties, cutting characteristics, and chip formation mechanisms. Cutting parameters have to be adapted for each material in order to achieve the demanded workpiece quality and optimal processes in respect of tool life and material removal rate. The focus of this research is the development of an in-process material identification algorithm. Thus, a cylindrical turning process is investigated for friction welded aluminum/steel shafts (EN-AW6082/20MnCr5). A universal monitoring approach is presented which detects the different materials process-parallel. For this purpose, cutting forces and spindle torque are linked with a dexel-based material removal model to determine monitoring parameters. The design of experiment method is used to validate the approach for various process parameters. Cutting speed and feed velocity are adapted for cylindrical turning operations based on the monitoring algorithm. As a result, material-specific cutting parameters are adjusted during the machining in order to optimize the material removal rate. Based on this approach, further process optimization can be implemented, like the improvement of chip formation, while machining hybrid workpieces.