A Review on Extrusion Additive Manufacturing of Pure Copper

Abstract

Copper, due to its high thermal and electrical conductivity, is used extensively in many industries such as electronics, aerospace, etc. In the literature, researchers have utilized different additive manufacturing (AM) techniques to fabricate parts with pure copper; however, each technique comes with unique pros and cons. Among others, material extrusion (MEX) is a noteworthy AM technique that offers huge potential to modify the system to be able to print copper parts without a size restriction. For that purpose, copper is mixed with a binder system, which is heated in a melt chamber and then extruded out of a nozzle to deposit the material on a bed. The printed part, known as the green part, then goes through the de-binding and sintering processes to remove all the binding materials and densify the metal parts, respectively. The properties of the final sintered part depend on the processing and post-processing parameters. In this work, nine published articles are identified that focus on the 3D printing of pure copper parts using the MEX AM technique. Depending on the type of feedstock and the feeding mechanism, the MEX AM techniques for pure copper can be broadly categorized into three types: pellet-fed screw-based printing, filament-fed printing, and direct-ink write-based printing. The basic principles of these printing methods, corresponding process parameters, and the required materials and feedstock are discussed in this paper. Later, the physical, electrical, and mechanical properties of the final parts printed from these methods are discussed. Finally, some prospects and challenges related to the shrinkage of the printed copper part during post-processing are also outlined.