Process of Pure Copper Fabricated by Selective Laser Melting (SLM) Technology under Moderate Laser Power with...

Area of Science:

• Materials Science
• Additive Manufacturing
• Thermal Engineering

Background:

• Pure copper (Cu) possesses excellent thermal conductivity, making it ideal for thermal management components.
• High optical reflectivity of copper presents challenges in selective laser melting (SLM), often requiring high laser power.
• Existing SLM methods struggle to produce high-quality copper parts efficiently due to these challenges.

Purpose of the Study:

• To demonstrate a re-melting strategy for fabricating high-density, low-surface-roughness pure copper parts using moderate laser power.
• To investigate the influence of the re-scan to initial scan speed ratio on printing quality.
• To provide an optimized approach for 3D printing pure copper components with enhanced properties.

Main Methods:

• Utilized a re-melting strategy during the selective laser melting (SLM) process.
• Varied the re-scan to initial scan speed ratio to analyze its effect on microstructure and surface quality.
• Optimized process parameters including laser power (350 W), hatch spacing (0.06 mm), powder layer thickness (0.05 mm), initial scan speed (200 mm/s), and re-scanning speed (400 mm/s).

Main Results:

• Achieved high-density pure copper samples (93.8% relative density) with low surface roughness (Sa~22.9 μm).
• The re-melting strategy acted as a localized annealing process, promoting recrystallization and improving microstructure.
• Successfully fabricated high-quality pure copper parts using only moderate laser power.

Conclusions:

• The re-melting strategy is an effective approach for overcoming the challenges of 3D printing pure copper with SLM.
• This method allows for the production of dense, smooth copper components at lower laser power, ensuring long-term stability.
• The findings have broad implications for 3D printing reflective metals, particularly for advanced thermal management applications.