Explore the feasibility of fabricating pure copper parts with low-laser energy by selective laser melting

Abstract

Pure copper is widely used for complex shapes, high thermal conductivity and good conductivity parts, such as heat exchangers, welding nozzles, injection molds, and various conductive parts. However, traditional manufacturing techniques are difficult to design complex pure copper parts into the most effective thermal and conductive structure. Selective Laser melting(SLM) can fabricate parts with complex shapes directly. However, due to the characteristics of easy oxidation, high optical reflectivity and high thermal conductivity, 3D printing pure copper by SLM is extremely challenging. In this study, the feasibility of fabricating pure copper by low-laser energy was studied by both numerical simulation and printing experiments, and the characteristics of the molten pool (molten pool structure, temperature flow and velocity flow) were studied. The results showed that due to its high thermal conductivity, heat spread out quickly in the molten pool, temperature rise rate and cooling rate reached as high as 1.36 × 10 ^7 K S ^−1 , 2.99 × 10 ^5 K S ^−1 respectively. And it took only about 1.7 × 10 ^–4 S for the process time of powder melting and solidification. Additionally, by reducing the particle size, the absorption rate for pure copper was improved, pure copper parts were successfully fabricated with low-laser energy: laser power 500 W, hatching space 0.07 mm, layer thickness 0.03 mm, laser scanning velocity 2500 mm s ^−1 .

Keywords

• SLM
• heat flow
• velocity flow
• pure copper
• low-laser energy
• heat and velocity flow