Selective laser melting technology development for grid and cellular medical materials

Introduction: The design and production of patient-specific medical implants with high biocompatibility and good regeneration features is a still challenging task. Selective laser melting (SLM) is one of the most promising methods for manufacturing products with complex shapes and structures. The work is aimed at the development of physical and technological foundations for obtaining a proper mesh structure by SLM.

Methods: Numerical simulation was performed using COMSOL software to reveal the dependencies between the temperature gradient and SLM's technological parameters. A COXEM EM-30AXPlus scanning electron microscope was utilized for powder elemental analysis and microtopography. An SLM-50 realizer was adopted to produce the samples using SLM technology.

Results and Discussion: The primary technical, chemical, and physical attributes of the CoCr, TiNi, and Ti6Al4V powders were ascertained. Regimes for the temperature field distribution in the fusion zone were developed, and the penetration depth was determined. The dependencies between the technological parameters of SLM and the geometric characteristics of the CoCr, TiNi, and Ti6Al4V thin-walled structures were established. Functional Ti6Al4V cellular structures with cell sizes of 2-3 mm and a bridge thickness of 200 to 300 μm were manufactured to replace bone tissue defects. TiNi and CoCr coronary stents with a diameter of 2 to 6 mm and a strut size of 150 μm to 500 μm were produced.

Conclusions: TheSLM regimes developed provide minimal deviations in wall thickness from the 3D model and the proper penetration depth for designing defect-free thin-walled mesh structures.

The study was funded by a grant ffrom the Russian Science Foundation, No. 23-79-01284: https://rscf.ru/project/23-79-01284/.