Laser re-scanning strategy in selective laser melting for part quality enhancement : a review

Abstract

The selective laser melting (SLM) process is a powder bed fusion additive manufacturing process that can produce near full-density parts for many high value applications in research and industry. Due to the use of laser, the laser re-scanning strategy (LRS) can be employed in SLM. LRS can be defined as the scanning strategy when any one of the part’s layer have more than one passes of laser scan (instead of just one pass under normal scanning circumstances). The laser re-scan can be of any extent, e.g. point, contour, or area. This comprehensive review covers the applications of LRS to enhance bulk properties, improve surface quality, relieve residual stresses, minimize defects and improve part’s accuracy. The challenges and future trends for LRS are also discussed.