Analysis of affecting factors of overhanging surface quality by selective laser melting

Overhanging structure is an inherent geometric process limitation of selective laser melting(SLM),which would easily reduce the shape and dimension accuracy of built parts.To find the causes of defects in building overhanging surface, overhanging structure building experiments were carried out on 316L stainless steel at different inclined angle,scanning length and different speed.The results showed that at smaller inclined angle and the lower scanning speed,more serious warpage would happen,and the theoretical minimum building angle and reliable building angle fit with the experimental results at high and low scanning speed.High-speed scanning can build the overhanging surface with the minimum building angle,while low-speed scanning can only build the overhanging surface with a reliable building angle.Wrap of scanned overhanging surface would be more likely to happen along the long line direction.By control of local processing parameters,the quality of overhanging surface can be significantly improved.The basis for building overhanging surface by SLM was provided from the perspective of process and design,and the preliminary solution was proposed.