Copper has excellent properties such as good ductility, good corrosion resistance, and excellent electrical and thermal conductivity, and has been widely used in many fields. Although 3D printing can provide many advantages through layer-by-layer manufacturing, 3D printing of high-purity copper remains challenging due to thermal issues caused by copper's high electrical conductivity. There have also been recent advances in high-purity copper 3D printing technology in the past few years. There are also advantages and current problems in high-purity copper 3D printing methods, and the different properties of copper parts printed by these methods are summarized. There are also several potential applications for 3D printed copper parts, and these developments may lead to new improvements in this field of advanced manufacturing.
Selective Laser Melting Selective Laser Melting (SLM) is a widely used powder bed-based metal part manufacturing process. The build process starts with spreading a thin layer of metal powder over the work area. The metal powder is usually fed by a hopper, while a coating blade is used to ensure that the powder is evenly distributed. Then, a galvanometer scanner is used to guide a high-energy density laser beam through the deposited layers of metal powder. According to the CAD data of the manufactured part, only the metal powder in the selected area is exposed to the laser beam and melts and fills the XY plane along the part contour. The build platform is then lowered and a new layer of powder is deposited for the next laser scanning step. These three steps are repeated until the desired part is fully built. The build plate is usually connected to support structures, which are necessary for the fixation of the part in the powder bed and for heat dissipation. Deformation of the printed part can be avoided by preheating the build plate to reduce thermal gradients and reduce residual stresses during the SLM process. Inert gas such as nitrogen or argon is continuously supplied to the build chamber to provide an inert atmosphere to protect the metal powder and the heated metal part from oxidation. After the printing process is completed, the substrate can be removed from the printed part. Important process parameters such as layer thickness, infill spacing, laser power and scanning speed need to be optimized to produce high-quality printed parts.
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