Flow analysis of the laminated manufacturing system with laser sintering of metal powder. Part I: flow uniformity inside the working chamber

摘要

Selective laser melting (SLM) as a part of 3D printing technology has been a novel industrial manufacturing process nowadays. However, the collection of metal powders emitted from the working plane is significant for the SLM process. The uniformity of the flow passing through the SLM working chamber, which helps collect emitted powders, has been considered as a key solution. In this study, for the purpose of improving the flow uniformity, a blow-to-suction device composed of a trapezoid push nozzle, a working chamber, and a suction tunnel was applied. Various parameters, such as the width of trapezoid push nozzle, the width of suction tunnel, and the nozzle-to-plane distances, were examined experimentally and computationally. Hot-wire velocity measurement and smoke flow visualization were used to verify the reliability of the simulation. Through the results of degree of uniformity (DOU), the momentum exchange between the suction and blow sides plays an important role for producing a uniform flow through the working chamber. In addition, higher suction velocity as well as larger nozzle-to-plane distance result in relatively better uniformity of the flow.