A parameter-variant trochoidal-like tool path planning method for chatter-free and high-efficiency milling

Trochoidal milling is known for its advantages in machining difficult-to-machine materials as it facilitates chip removal and tool cooling. However, the conventional trochoidal tool path presents challenges such as lower machining efficiency and longer machining time due to its time-varying cutter-workpiece engagement angle and a high percentage of non-cutting tool paths. To address these issues, this paper introduces a parameter-variant trochoidal-like (PVTR) tool path planning method for chatter-free and high-efficiency milling. This method ensures a constant engagement angle for each tool path period by adjusting the trochoidal radius and step. Initially, the nonlinear equation for the PVTR toolpath is established. Then, a segmented recurrence method is proposed to plan tool paths based on the desired engagement angle. The impact of trochoidal tool path parameters on the engagement angle is analyzed and coupled this information with the milling stability model based on spindle speed and engagement angle to determine the desired engagement angle throughout the machining process. Finally, several experimental tests are carried out using the bull-nose end mill to validate the feasibility and effectiveness of the proposed method.