The applications of particle image velocimetry (PIV) to experimentally observe the flow behaviors inside the Selective Laser Melting (SLM) working chamber

In order to maintain the flow uniformity and prevent the ejecting metal powders across the working chamber of Selective Laser Melting (SLM), for the purpose of obtaining the high quality products, flow observations inside the chamber need to be carefully conducted. This study proposed the technique of particle image velocimetry (PIV) for investigating the flow characteristics inside the SLM chamber, with examining two elliptical blowing nozzles with different aspect ratios (ARs). The mean velocity distributions, turbulence intensities, vorticities and Reynolds stress were analyzed to evaluate the performances of the two nozzles, Ellipse 1 and Ellipse 2. The experimental results demonstrated that Ellipse 1 with higher AR were more suitable for SLM operation, owing to the faster velocity decay, the higher spread rate and entrainment and the smaller stagnation region.