Assembly-free design for additive manufacturing of articulated components based on layered precision assignment

This paper presents an assembly-free design method for additive manufacturing (AM) of articulated components based on layered precision assignment (LPA). The articulated components are top-down decomposed into physically separated or nearly disconnected entities in different types of fit with specific clearance, for layered slicing hereafter. The forward design method sequentially integrates build orientation, adaptive slicing, trajectory optimization, in conjunction with machine uncertainty of 3D printing (3DP). Besides geometric analysis, the machine uncertainty owing to vibration and thermal coupling is considered by establishing general precision model of kinematic chain errors. By utilizing integrated digital twins (DT), the material extruding process can be visualized synchronously during fabrication process, with the support of a series of online sensor metadata. The manufacturing precision at each layer can be allocated and assigned with accurate distribution, on the basis of trajectory error assessment. The physical experiment of human lumbar vertebrae is carried out to verify the proposed method. The experiment proves that the proposed LPA is fundamentally adaptive to non-assembly 3DP of a variety of even alternative processes with multi-materials under machine uncertainty.