Powder-spreading dynamics and packing quality improvement for laser powder bed fusion additive manufacturing

Abstract

The powder-spreading process is crucial to the powder layer's packing quality. In this study, powder-spreading dynamics under different substrate surface roughness are investigated. Furthermore, the effects of spreading speed, layer thickness, and substrate surface texture orientation on powder layer packing quality are analyzed. It is discovered that the rough substrate surface contributes to the inhibition of particles from the substrate and contributes to the kinetic intensity and diversity of particles. The spreading speed is beneficial to particle dynamics but adversely affects the packing quality. The layer thickness and substrate surface texture orientation minimally affected the powder-spreading dynamics but significantly affected the packing density. Based on the results: a high spreading speed with an appropriately large layer thickness is a feasible method to resolve the conflict between the spreading efficiency and packing quality; the angle between the laser scan and powder-spreading directions should keep constant during the entire forming process.