Electrical Conductivity of Additively Manufactured Copper and Silver for Electrical Winding Applications

Area of Science:

• Materials Science
• Additive Manufacturing
• Electrical Engineering

Background:

• Efficient electrical machines are crucial for green energy technologies, requiring compact custom windings.
• Additive Manufacturing (AM) of copper (Cu) and silver (Ag) offers potential for improved efficiency and thermal management.
• Laser Powder Bed Fusion (L-PBF) of highly conductive metals like Cu and Ag is challenging due to low energy absorption.

Purpose of the Study:

• To investigate the feasibility of 400 W L-PBF for fabricating high-purity Cu, Ag, and Cu-Ag alloy electrical windings.
• To characterize the influence of material composition, powder recoating, laser exposure, and electropolishing on electrical conductivity.
• To establish electropolishing parameters for improved surface roughness for insulation coating applications.

Main Methods:

• Utilized a 400 W Laser Powder Bed Fusion (L-PBF) system to process high-purity Cu, Ag, and Cu-Ag alloys.
• Investigated six material variants across four comparative studies, varying parameters such as material composition and laser exposure.
• Characterized the density and electrical conductivity of the printed materials and optimized surface roughness via electropolishing.

Main Results:

• Achieved a maximum material density of 88% and electrical conductivity of 73% International Annealed Copper Standard (IACS).
• Identified key processing parameters influencing the quality and conductivity of L-PBF processed Cu and Ag.
• Successfully fabricated proof-of-concept electrical machine coils, demonstrating the viability of the process.

Conclusions:

• 400 W L-PBF is a viable method for fabricating custom copper and silver electrical machine windings.
• The study advances the state-of-the-art in AM for high-conductivity metals, enabling next-generation electrical machines.
• Optimized processing and post-processing (electropolishing) are critical for achieving high electrical performance and surface quality.