Process parameter interval sensitivity and optimization of machined surface roughness for high-speed milling of titanium alloys

High-speed milling of titanium alloys is widely used in aviation and aerospace industries for its high efficiency and good quality. To realize surface roughness-oriented process control in high-speed milling, this article puts forward the concepts of process parameter sensitivity and relative sensitivity based on a surface roughness empirical model. By an orthogonal experiment of high-speed end milling, mathematical models of the process parameter sensitivity and relative sensitivity are built. Based on an analysis of the process parameter interval sensitivity, the planning principle and method for the process parameter stability region and instability region are proposed. Using the extreme difference analysis method facing the orthogonal experiment, the influencing curves of process parameters on surface roughness are obtained. Then, according to the influence curves, the optimum selection of the cutting process parameter interval is proposed. The results show that the surface roughness of high-speed milling of a titanium alloy is most sensitive to the variation of the cutting speed, next sensitive to the feed per tooth, and it is least sensitive to cutting width and depth. The optimum cutting speed ranges from 314 m/min to 377 m/min, and the optimum feed per tooth ranges from 0.03 mm/z to 0.05 mm/z. The optimum cutting parameters can control the roughness below the value of 0.6 μm. The theoretical analysis and test data presented in this article can be used for optimizing high-speed milling parameters of titanium alloys to control surface roughness.