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 multi-spot 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 μm. Moreover, the scanning time was decreased by 38.1% of the single-spot method.