Optimal process parameters for parallel turning operations on shared cutting surfaces

• The dynamics of parallel turning processes are modeled in time and frequency domain.
• Parallel turning processes with and without dynamic transfer coupling are considered.
• A notable dependency of the process stability on the radial angle is observed.
• The results confirm a high potential to optimize the overall cutting performance.

To enhance productivity in industrial settings, turning machines are increasingly being used with multiple turrets. This machine configuration enables parallel machining at different or at the same cutting surface using independent tools. However, there is a dynamic interaction between the cutting processes due to the waviness induced on the shared cutting surface as well as due to the dynamic coupling through the machine structure. This dynamic interaction can lead to a significant reduction of the chip removal rate compared to two conventional processes. To utilize the productivity advantage of parallel turning processes, an examination of the process-machine-interaction considering the dynamic coupling of the cutting processes is required. Hence, this paper discusses parametrization for stable processing of parallel turning operations. Therefore, time and frequency domain-based simulation models are developed and matched with experimental cutting tests. Additionally, the influence of the radial angle between the tools is investigated. This angle influences the dead time between two successive cuts for parallel turning processes on the same cutting surface. The dead time in turn directly affects the process stability limit. Thus, with the help of the developed simulation models, an optimal process parametrization for parallel turning operations can be determined.