Improving the Mechanical Strength of Dental Applications and Lattice Structures SLM Processed

• Published in: Materials Vol. 13; no. 4; p. 905
• Main Authors: Cosma, Cosmin, Kessler, Julia, Gebhardt, Andreas, Campbell, Ian, Balc, Nicolae
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 18.02.2020; MDPI AG
• Subjects: particle shape; particle size; process parameters; processability index; stainless steel; tensile strength; particle size; particle shape; processability index; tensile strength; process parameters; stainless steel
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma13040905

To manufacture custom medical parts or scaffolds with reduced defects and high mechanical characteristics, new research on optimizing the selective laser melting (SLM) parameters are needed. In this work, a biocompatible powder, 316L stainless steel, is characterized to understand the particle size, distribution, shape and flowability. Examination revealed that the 316L particles are smooth, nearly spherical, their mean diameter is 39.09 μm and just 10% of them hold a diameter less than 21.18 μm. SLM parameters under consideration include laser power up to 200 W, 250-1500 mm/s scanning speed, 80 μm hatch spacing, 35 μm layer thickness and a preheated platform. The effect of these on processability is evaluated. More than 100 samples are SLM-manufactured with different process parameters. The tensile results show that is possible to raise the ultimate tensile strength up to 840 MPa, adapting the SLM parameters for a stable processability, avoiding the technological defects caused by residual stress. Correlating with other recent studies on SLM technology, the tensile strength is 20% improved. To validate the SLM parameters and conditions established, complex bioengineering applications such as dental bridges and macro-porous grafts are SLM-processed, demonstrating the potential to manufacture medical products with increased mechanical resistance made of 316L.