Comparison of the Structure and Properties of the Solid Co-Cr-W-Mo-Si Alloys Used for Dental Restorations CNC Machined or Selective Laser-Sintered

What is it about?

The purpose of the paper is comparing the impact of SLS selective laser sintering technology and CNC machining methods on the structure and properties of solid Co-Cr-W-Mo-Si alloys. Structural tests were carried out using the X-ray structural analysis, EDS chemical composition analysis, metallographic investigations using stereoscopic, light and scanning electron microscopes using computerized methods of quantitative metallography and tests of tensile, bending and compression strength. Individually designed micro samples were used, and the results were statistically processed. It has been shown that if optimal conditions of SLS technology are used, it is possible to obtain a structure with a pore content of 0.1% smaller than in the case of solid cast materials. That ensures better mechanical properties than cast materials. At the same time, it was pointed out that even minor technological errors associated with SLS technology cause a lowering of all strength properties associated with a significant increase in porosity by up to 10%. Allowing small changes in technological conditions, including such as the width of the laser spot, the width of the laser beam, the allowance associated with the overlap of the laser beam, disturbances in the flow of inert gas, uncontrolled changes in the laser power can cause a significant reduction in strength. A plug & play approach is unacceptable. If even one layer with a thickness of 25 μm is produced in suboptimal conditions, the manufactured element can do not meet the assumed requirements. The use of SLS additive technology for the production of prosthetic components made of Co-Cr alloys is the best choice among the methods currently used in dentistry. The use of SLS technology together with the digitization of design and manufacturing processes is an important element in implementing the Dentistry 4.0 approach as part of the Industry 4.0 stage of the industrial revolution.

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