Electrical resistivity of pure copper processed by medium-powered laser powder bed fusion additive manufacturing for use in electromagnetic applications

Abstract

Pure copper is an excellent thermal and electrical conductor, however, attempts to process it with additive manufacturing (AM) technologies have seen various levels of success. While electron beam melting (EBM) has successfully processed pure copper to high densities, laser powder bed fusion (LPBF) has had difficulties achieving the same results without the use of very high power lasers. This requirement has hampered the exploration of using LPBF with pure copper as most machines are equipped with lasers that have low to medium laser power densities. In this work, experiments were conducted to process pure copper with a 200W LPBF machine with a small laser spot diameter resulting in an above average laser power density in order to maximise density and achieve low electrical resistivity. The effects of initial build orientation and post heat treatment were also investigated to explore their influence on electrical resistivity. It was found that despite issues with high porosity, heat treated specimens had a lower electrical resistivity than other common AM materials such as the aluminium alloy AlSi10Mg. By conducting these tests, it was found that despite having approximately double the resistivity of commercially pure copper, the resistivity was sufficiently low enough to demonstrate the potential to use AM to process copper suitable for electrical applications. Highlights• Medium powered LPBF machines can process pure Cu to an acceptable level.• Resistivity of as-built Cu increases by 33% depending on initial build orientation.• Resistivity can be reduced by over 50% from as-built conditions via heat treatment.• Electrical resistivity values once heat treated are lower than AlSi10Mg values.

Powder-Based 3D Printing for the Fabrication of Device with Micro and Mesoscale Features

“…Another area where powder-based 3D printing could contribute is the manufacturing of electrodes. The aim is to fabricate pure copper electrodes with the highest possible density for lowest possible electrical resistivity using minimal laser power [ 211 ]. The minimum feature size of a thin electrode was approximately 200 µm.…”

Sliding Mean Value Subtraction-Based DC Drift Correction of B-H Curve for 3D-Printed Magnetic Materials

“…The printing of several different materials using selective laser melting (SLM) is available in the literature. The SLM fabrication of conductive (Cu [10], AISi10MG [11]) and soft ferromagnetic (FeSi6.7 [12], FeSi6.9 [13], FeSi3 [14], Fe-Co-V [15], Fe-Ni-Si [16]) materials are well explained in the literature.…”

Laser Powder Bed Fusion of Metal Coated Copper Powders

“…It is also possible to produce materials with spatially varying microstructures, or including metastable phases [4,5]. L-PBF has become an industrially relevant method for manufacturing small batches or individualized parts quickly [6].…”

“…When processing copper powder at laser powers available in many commercial L-PBF machines, typically around 200-400 W, the parts are characterized by a relatively high level of porosity [6,7]. These porosities are often a result of balling [8], a defect characterized by the powder agglomerating into balls or tubes with a diameter larger than the powder diameter along the laser track.…”