In-situ experiment tests and particulate simulations on powder paving process of additive manufacturing

Abstract

In this work, in-situ experimental tests are first performed to investigate the powder spreading process of additive manufacturing, where different kinds of scrapers and spreading speeds are employed. Detailed kinetic behaviours of individual powder particles are discussed by discrete element method simulations. It is found that the decrease of inclination angle of the scraper improves the powder pressure and compaction in the spreading process, leading to a denser powder flow and thus a denser powder bed. The increase of spreading speed also improves the powder pressure and compaction in the spreading process. However, the powder flow becomes looser due to the volume dilation, and thus the quality of the paved powder bed decreases. In industrial applications, if the higher powder spreading speed is employed to improve the processing efficiency, the scraper with a smaller inclination angle can be used to ensure the powder bed quality.