Preventing Evaporation Products for High-quality Metal Film in Directed Energy Deposition: A Review

Directed Energy Deposition (DED) is a process that enables high-speed deposition with a sub-millimeter thickness using laser technology. Thus far, defect studies on additive manufacturing, including DED, have focused mostly on preventing pores and crack defects that reduce fatigue strength. On the other hand, evaporation products, fumes and spatters, generated by the high energy have often been neglected despite being some of the main causes of porosity and defects. In high-quality metal deposition, the problems caused by evaporation products are difficult to solve, but they have not yet caught the attention of metallurgists and physicists. This review examines the effect of the laser, material, and process parameters on the evaporation products to help obtain a high-quality metal film layer in thin-DED.