Exploration of synchronized dual-beam laser melting with high speed video imaging

Abstract

Multilaser powder bed fusion machines are gaining prominence in industry due to their increased productivity. Mitigating spatter interactions requires separating the lasers physically or temporally, which can lead to inefficient laser processing. Therefore, each additional laser potentially has a diminishing effect on build time reduction. By contrast, two synchronized lasers in close proximity can operate as one beam, resulting in the formation of a single melt pool. This configuration can potentially avoid negative laser interactions and increase the build rate beyond what is achievable with two distinct beams. This work discusses high-speed video imaging of a synchronized dual-beam system to assess the laser interactions for 316L. Additionally, the video results are used to validate a thermal model simulating the temperature field of this synchronized strategy. A width prediction error of 6.0% (averaged) or 22.9% (maximum) is found. The model is capable of predicting the coalescence of both melt pools with high reliability except for 1 out of 41 investigated cases, in the transition zone between individual to coalesced melt tracks.