Theoretical Analysis of the Coincident Wire-Powder Laser Deposition Process

Abstract

The process of coincident wire and powder deposition by laser has recently emerged in research work as a layered manufacturing method with a higher deposition rate than the established laser direct metal deposition technique and as a means of creating functionally graded metallic surface layers in a single pass. This work analytically models the process by accounting for the incoming wire and powder as virtual negative heat sources. The major assumptions of the model are confirmed experimentally and the predicted temperature profiles compared with values measured using contact and pyrometric methods. Model accuracy outside the molten zone is excellent, but this solution does not account for latent heat and intrapool circulation effects so it gives only moderate precision when extrapolated to within the melt pool. Increasing the mass feed rate to the melt pool reduces its depth and the temperature surrounding it—these effects can be quantified in three dimensions by the model.