Laser sintering of cold-pressed Cu powder without binder use

Constantin, Loïc; Fan, Lisha; Mortaigne, B.; Keramatnejad, Kamran; Zou, Qiming; Azina, Clio; Lu, Yong Feng; Silvain, Jean François

doi:10.1016/j.mtla.2018.08.021

Cited by 7 publications

(5 citation statements)

References 17 publications

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“…Low-density parts (86%) with low thermal conductivity (TC) of 202 W/m•K were reported. The low-density parts resulted from insufficient laser energy deposited on powders due to the fast heat dissipation rate and the low laser absorption in the near-infrared (IR) domain of Cu [14,15]. High laser power (800 W) was employed to overcome this issue, and dense Cu parts were printed (97%) with a TC of 336 W/m•K [16,17].…”

Section: Introductionmentioning

confidence: 99%

Laser 3D printing of complex copper structures

Constantin

et al. 2020

Additive Manufacturing

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The ability to design complex copper (Cu) parts into the most efficient thermal structures is an old dream, but difficult to realize with conventional manufacturing techniques.The recent development of laser 3D printing techniques makes it possible to fully explore intricate designs and maximize the thermal performance of Cu-based thermal management components but present significant challenges due to its high optical reflectivity. In this study, we demonstrated the laser 3D printing of pure Cu with a moderate laser power (400 W). Dense Cu parts (95 %) with smooth surface finishing (Ra ~18 μm) were obtained at a scan speed of 400 mm/s, a hatch distance of 0.12 mm, and a layer thickness of 0.03 mm. The hardness, electrical, and thermal conductivity of the printed Cu parts are 108 MPa, 5.71×10 7 S/m, and 368 W/m•K, respectively, which are close to those of bulk Cu. Additionally, complex heat sink structures were printed with large surface areas (600 mm 2 /g), and their cooling performances were compared to a commercial heat sink with a smaller surface area (286 mm 2 /g) on an electronic chip. The complex heat sinks printed cools the electronic chip 45% more efficiently than the commercial one. The introduction of selective laser melting to additively manufacturing Cu heat sinks offers the promise to enhance the performance beyond the scope of exciting thermal management components.

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Section: Introductionmentioning

confidence: 99%

Laser 3D printing of complex copper structures

Constantin

et al. 2020

Additive Manufacturing

Self Cite

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“…where E is the energy density in Joules per square meter, P is the laser power in Watts, V is the scanning speed of the laser, and d is the spot-size diameter. The fast heat dissipation rate of Cu, low laser absorption rate in the near-infrared (IR) region, and the low-density components were caused by insufficient laser energy being deposited on powders [38,39]. However, the addition of CNTs increased the absorption of laser energy to the Cu-CNTs composite, which resulted in increased densification of the powder particles.…”

Section: Optimization Of Energy Densitiesmentioning

confidence: 99%

Investigation on Optical Absorption and Reflection of Carbon Nanotubes Mixed Copper Composites for Laser Sintering Process Improvement

Ayub,

Khan,

McCarthy

et al. 2023

Metals

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Selective laser sintering (SLS) of copper components manufactured via powder metallurgy is widely studied due to minimal material wastage. However, copper has poor optical absorption when exposed to infrared (IR) lasers, such as in laser-based additive manufacturing or laser surface processing. To address this issue, an innovative approach to enhance the optical absorption of copper powders during infrared laser sintering is presented in this study. Carbon nanotubes (CNTs) have several unique properties, including their high surface area, plasmonic response, excellent conductivity, and optical absorption properties. CNTs were mixed with copper powders at different weight percentages using an acoustic method. The resulting Cu-CNT compositions were fabricated into pellets. The Box-Behnken Design of Experiments methodology was used to optimize the IR laser processing conditions for sintering. Spectroscopic analysis was conducted to evaluate the reflection and thermal absorption of the IR wavelengths by the Cu-CNT composites. Density and hardness measurements were taken for the laser-sintered Cu-CNT pellets. The coating of copper powders with CNTs demonstrated enhanced optical absorption and correspondingly reduced reflection. Due to the enhanced optical absorption, increased control and sensitivity of the laser sintering process was achieved, which enabled improvement in the mechanical properties of strength, hardness, and density, while also enabling control over the composite thermal expansion coefficient. A maximum average hardness of 66.5 HV was observed. Indentation test results of the samples revealed maximum tangential and radial stresses of 0.148 MPa and 0.058 Mpa, respectively.

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“…However, there have been few attempts to form highly dense pure copper by SLM. The low-density parts resulted from insufficient laser energy deposited on powders due to their high thermal conductivity and low laser absorptivity [12,13].…”

Section: Introductionmentioning

confidence: 99%

Selective Laser Melting of High Relative Density and High Strength Parts Made of Minor Surface Oxidation Treated Pure Copper Powder

Yang

Guo

et al. 2021

Metals

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Pure Copper (Cu) is very difficult to prepare using selective laser melting (SLM) technology. This work successfully prepared the pure Cu with high relative density and high strength by the SLM technology using a surface oxidation treatment. The gas-atomized pure Cu powder was used as the feedstock in this work. Before the SLM process, the pure Cu powder was initially handled using the surface oxidation treatment to coat the powder with an extremely thin layer of Cu2O. The SLMed highly dense specimens contain α-Cu and nano-Cu2O phases. A relationship between the processing parameters (laser power (LP), scanning speed (SS), and hatch space (HS)) and density of Cu alloy in SLM was also investigated. The microstructure of SLMed Cu consists of fine grains with grain sizes ranging from 0.5 to ~30 μm. Tensile testing and detailed microstructural characterization were performed on specimens in the as-SLMed and pure copper state specimens. The mechanical property experiments showed that the specimens prepared by SLM technology containing nano-oxide phases had higher yield strength and tensile strength than that of other SLM-built pure copper. However, the elongation was remarkably decreased compared to other SLM-built pure copper, due to the fine grains and the nano-oxides.

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Laser sintering of cold-pressed Cu powder without binder use

Cited by 7 publications

References 17 publications

Laser 3D printing of complex copper structures

Laser 3D printing of complex copper structures

Investigation on Optical Absorption and Reflection of Carbon Nanotubes Mixed Copper Composites for Laser Sintering Process Improvement

Selective Laser Melting of High Relative Density and High Strength Parts Made of Minor Surface Oxidation Treated Pure Copper Powder

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