Research And Implementation Of Path Planning Algorithm For Thin-walled Parts In Powder Bed Additive Manufacturing

Additive manufacturing technology is a new layer-by-layer manufacturing method.Compared with traditional subtractive manufacturing,it has the advantages of simple process and high manufacture efficiency.In powder bed metal additive manufacturing,rapid melting and solidification of metal powders will produce steep temperature gradients,resulting in large residual stresses in the components,which will lead to defects such as warpage and deformation,and ultimately affect the overall performance of the parts.Scanning strategy is one of the key factors affecting the quality of the manufactured parts.In the powder bed additive manufacturing process,it is difficult to obtain thinwalled parts of ideal quality with the conventional scanning path.A partitioned scanning path planning strategy based on medial axis transformation is proposed to reduce the residual stress and control the distribution.The main research contents of this thesis are as follows:(1)A medial axis transformation algorithm suitable for multi-connected polygons is studied,and the medial axis transformation of the layered solid area of additive manufacturing is implemented.(2)A method for prunning the medial axis based on the size of the affected area of the medial axis is proposed,and the layered solid area is partitioned according to the pruned medial axis.(3)A partitioned scanning method for thin-walled parts molding is proposed,based on the transformation of the medial axis.The area to be scanned is divided into the main area and the connecting area,and a sinusoidal scanning path and a regular triangle mesh scanning path are designed for the main area and the connecting area respectively.Finally,the result of a typical multi-connected and thin-walled model is given.