On recoated powder quality with a forward rotating flexible roller in laser powder bed fusion of 30 wt% 5 μm SiCp/AlSi10Mg composites

This paper proposes a new powder recoating mechanism named forward rotating flexible roller (FRFR) which aims to solve the poor powder flowability problem brought by the aggregation effect of the fine particles in the mixed 30 wt% 5 μm SiC and 55 μm AlSi10Mg powder. An initial extrusion force instead of a gap between the flexible roller and powders is used to improve the recoated powder density, while the recoated powder layer thickness is proved to be controllable. An industrial camera and a laser displacement sensor were used to estimate the recoated surface filling rate and recoated surface profile. The mixed powder was recoated with an FRFR on a baseplate at first, the achieved surface filling rate was the same as that of 55 μm AlSi10Mg recoated with a rubber blade. Then 120 layers of mixed powder were recoated continuously with FRFR, the recoated surface profile within a single layer and between multiple layers were compared with the rubber blade recoated AlSi10Mg, their difference is insignificant. Furthermore, composite parts with different shapes were successfully made with the FRFR. This technique is proved to be promisihfcang for laser powder bed fusion of fine particle ceramic and metal mixed powder.