Prediction of chatter stability for enhanced productivity in parallel orthogonal turn-milling

To increase productivity and the material removal rate, an increasing number of factories have been employing multiple tools for simultaneous cutting. Among these tools is parallel orthogonal turn-milling, which is an important parallel-processing method. However, a dynamic interaction occurs during the cutting processes due to the waviness induced on the shared cutting surface and the dynamic coupling through the machine structure, creating machining vibrations, or chatter, which affect the quality of the machined surface. Therefore, to reduce or avoid the vibration problem during the cutting process, chatter stability of parallel orthogonal turn-milling was examined in this study. Initially, a chatter mechanism model of parallel orthogonal turn-milling was designed, and the limit-critical axial depth of the cut formula was obtained. Next, the model parameters of the machine tool were obtained based on the hammer test method. A parallel orthogonal turn-milling stability lobe diagram (SLD) with tool tip runout was constructed. Finally, the experimental results were verified on a high-efficiency turn-milling machine tool. The results showed that chatter can be predicted for parallel orthogonal turn-milling and an SLD can provide a reference for the selection of machining parameters. In addition, the SLD can also guide the formulation of processing technology specifications. Our results are extremely significant for ongoing research in the field of machining methods.