Effect of Abnormal Powder Feeding on Mechanical Properties of Metallic Fabricated Part in Directed Energy Deposition

Abstract

Directed energy deposition (DED) is utilized in the automotive, aerospace, and defense industries for defect repair and remanufacturing. Stable powder feeding through nozzles for the quality of parts is crucial in the DED process. Even if the powder flow changes due to a defect in the powder feeding nozzle, it is difficult to confirm visually and similarly difficult to ensure defects in additively manufactured parts unless there is significant distortion. Therefore, a prior understanding of the quality degradation and development mechanism for process defects of abnormal powder feeding is necessary, and the phenomenon of product defects must be observable. This study analyzed the shape and mechanical properties of parts according to abnormal powder feeding caused by nozzle failure. Computational fluid dynamics analysis examined the physical phenomena resulting from the abnormal supply. When the nozzle is obstructed, there is an abnormal supply of powder, which leads to defects in additively manufactured part due to the asymmetry of the melting pool flow and temperature distribution.

Keywords: Directed Energy Deposition, Clogged nozzle, Abnormal powder feeding, Process defect, Computational Fluid Dynamics