Influence of multi-spot exposure of powder bed on melt pool stability in selective laser melting

Abstract

Part quality and building time during selective laser melting strongly correlates with the quality of the melting tracks and the melting rate respectively. Conventional processes can be improved by changing their parameters. Increase of the building rate is achieved by modifying the laser beam properties, e.g. spot size and laser power, and process parameters, such as layer thickness and scanning speed. However, process acceleration often leads to appearance of balling, spatters, evaporation and undercuts with subsequent degradation of component quality. The present investigation introduces an innovative way towards increasing of melting rate without lowering part quality. In our approach, the laser beam energy is efficiently distributed on the powder bed by means of beam splitting. This leads to the generation of high volume melt pools. Finally, an outlook on further increase of the melting rate is given.