Synchronized multi-spot scanning strategies for the laser powder bed fusion process

The laser powder bed fusion (LPBF) process can produce parts with complex internal geometries that cannot be easily manufactured using a material removal process. However, owing to the different heat transfer efficiencies of a laser melting process, the optimal process parameters are limited to a small range. This study used galvanometric scanner technology and a diffractive optical element (DOE) to build an experimental multi-spot LPBF system. Adjustable characteristics were the angle and the lateral distance between spots. An adjustable multispot method was used to modulate the temperature field on the powder bed and enhance the processing quality and throughput. The results from the synchronized three-spot method using different scanning strategies improved the layer surface roughness Ra by 3.2 mu m. Moreover, the scanning time was decreased by 38.1% of the single-spot method.