Multi-layer cutting path planning for composite enclosed cavity in additive and subtractive hybrid manufacturing

Additive and subtractive hybrid manufacturing (ASHM) refers to the hybrid manufacturing process where in-situ subtractive machining (SM) is introduced during additive manufacturing (AM). Its process characteristics dictate the necessity of planning multi-layer cutting paths in ASHM. Currently, the slice-based planning method cannot plan multi-axis cutting paths, and the machining accuracy is difficult to directly control. Meanwhile, the manual layering planning method is inefficient when dealing with complex models. Consequently, this paper presents an innovative automatic planning method for multi-layer, multi-axis, interference-free cutting paths with controllable precision in ASHM of composite enclosed cavity parts. To enhance the ASHM efficiency, criteria for the recognition of hybrid machining features (HMFs) have been defined to identify HMFs within the model. The identification of interference planes during cavity conversion has been achieved, and these interference planes are then utilized as the conversion planes for the ASHM process. Furthermore, a boundary-guided method is employed to automatically plan the overall cutting path for HMFs. According to the G-code standard, the overall cutting paths are then output to the corresponding cutting path file within the height interval of the conversion planes. Through practical machining, it has been demonstrated that the proposed method can significantly enhance the efficiency and automation of the data preparation process in ASHM, while also improving the surface quality and dimensional accuracy of the AM part.