Direct Metal Laser Sintering of Precious Metals for Jewelry Applications: Process Parameter Selection and Microstructure Analysis

Direct Metal Laser Sintering (DMLS) is an advanced additive manufacturing (AM) technique for the 3D printing of metals. This technology is also beneficial in the jewelry industry, where precious metals are used, and the design and price are determinative factors. In this paper, the metal 3D printing process for jewelry production is discussed. Four rings made of gold, silver, titanium, and stainless-steel 316L have been designed and fabricated by AM machine based on the DMLS technique. Proper geometry and parameters for rings and support structure were determined. Results showed that a reduced amount of powder was required for 3D printing of metal rings using a locally developed AM machine. Besides, appropriate geometry and parameters for a jewelry box with a complex design have been specified to be fabricated from stainless steel 316L by the same AM machine. The quality of the final produced parts using DMLS technology was not demonstrated inferior compared to the quality of parts built by conventional manufacturing methods. Furthermore, utilizing an electron microscope the microstructures of the fabricated parts were obtained and analyzed in detail before and after polishing on the polisher machine. Results revealed that the maximum homogeneous surface was obtained for the gold and titanium samples, while the surface of the samples of stainless steel and silver had internal cavities, pores, and other defects. Also, it was concluded that usage of gold and silver for the manufacturing of jewelry product that does not experience heavy loads is quite justified.