3DBaz – Research from the FEM Research Institute for Precious Metals and Metals Chemistry in Germany demonstrates a method of selective laser melting (SLM) in gold. The method could give more design freedom to 3D printed jewelry, watches, and even electronics that use gold as a conductor.
Though SLM is a popular method for 3D printing titanium, aluminium or steel alloys, the authors explain that “Gold and silver alloys are very difficult to process by laser melting because of their high reflectivity and thermal conductivity.”
In order to refine these qualities for 3D printing, the researchers combine gold with other metal alloys such iron (Fe) and germanium (Ge). The success of each additional alloy is measured for its hardness, and an ability to mix without creating notable changes to the color of the yellow gold.
Ge001 and Fe003 strains were found to be the most applicable for additive manufacturing. As the Fe and Ge powders are oxidised, these combinations result in less light being reflected by the gold alloy.
The FEM Research Institute use an MLab R Laser CUSING machine from Concept Laser for the study. For each alloy combination, additive manufacturing settings are also changed. To this effect, the paper concludes with the optimal parameters for 3D printing gold alloy on the machine. These include:
- Optimal powder size: 5–30 μm.
- Ideal laser speed: 200–450 mm/s.
- Reduced porosity with heat treatment from 3-4% to 0.7%
- Additional porosity control with “Alloying additions of Fe and Ge”
Source : 3DPI