The influences of process parameters on the thermo-mechanical workpiece load and the sub-surface residual stresses during peripheral milling of Ti-6Al-4V

Abstract The residual stress state of the sub-surface zone is a significant influencing factor, which determines the strength, lifetime and reliability of a component after machining. A reliable adjustment of this surface characteristic during peripheral milling is currently not possible. It is desired to control the milling process using a model-based approach in order to generate defined residual stresses in titanium components. This paper focuses on the determination of the thermo-mechanical load leading to the residual stress state during peripheral milling of Ti-6Al-4V. A newly developed sensory tool holder for the in-process measurement of the temperatures in the process zone was used. The influence of the process parameters cutting speed, feed per tooth, and radial depth of cut on the residual stress condition is shown. In addition, the varying microgeometry of the tool due to tool wear is taken into account as an observable disturbance variable.