A kinematics-aware decomposition approach for complex CAD parts in additive manufacturing

Improving the surface quality of each assembly interface on a CAD part in Additive Manufacturing (AM) can effectively promote the part's kinematic performance in a product or a prototype. To achieve this goal, decomposition is frequently unavoidable for a complex CAD part when it has two or more assembly interfaces respectively requiring different fabrication orientations to achieve their best surface quality. Accordingly, a smart and kinematics-aware part decomposition approach is proposed in this paper, in viewing that the related automatic works seldom ensure the achievement of the above goal while the manual operation is usually experience-intensive and time-consuming. First, the new criteria for kinematics-aware part decomposition are defined under the standard guidelines in ISO/ASTM 52910. Meanwhile, the heuristic method to determine the kinematics-aware fabrication orientation (to achieve the best surface quality) for an assembly interface is also presented. Based on them, a novel dual-process method is designed to decompose a CAD part from coarse to fine. It presents an assembly-interface-group-based method to plan the preliminary decomposition scheme, and then develops an optimization method to accurately determine all the decomposition planes based on the above scheme. Finally, experiments on six representative CAD parts are implemented to verify the effectiveness of the proposed approach. Comparing with the approaches that improve global and local surface quality based on optimizing fabrication orientation, the proposed approach increases more than 82% in the surface quality of the assembly interfaces on each part respectively. Besides, the methodological comparisons with the state-of-the-art approaches are also implemented. The results show that the proposed approach is more suitable for the applications where parts are fabricated using AM for the products or prototypes with mechanisms.