Theoretical and numerical researches on the electrochemical polishing of dental prostheses realized by selective laser melting

Mechanical and Surface Characteristics of Selective Laser Melting-Manufactured Dental Prostheses in Different Processing Stages

“…Metal additive technologies from the powder bed fusion (PBF) family open more and more opportunities for modern industries due to their ability to generate the most complicated metal parts with high precision and density in a relatively short time and enhance the final products in terms of geometrical features and in terms of some physical–mechanical properties. Selective laser depositions from the category of PBF additive technologies consist in applying a thin layer of powder with a fine granulation with a special leveling device, after which this powder bed is processed by means of a powerful laser beam or electron beam, melting spherical granules in the place of its projection [ 1 , 2 , 3 ]. The selective laser deposition group of technologies includes Selective Laser Sintering (SLS) [ 4 ], Direct Metal Laser Sintering (DMLS) [ 5 ], and selective laser melting (SLM) [ 6 ], which have a similar operating principle, the difference referring to the way the granules are bound.…”

“…The selective laser deposition group of technologies includes Selective Laser Sintering (SLS) [ 4 ], Direct Metal Laser Sintering (DMLS) [ 5 ], and selective laser melting (SLM) [ 6 ], which have a similar operating principle, the difference referring to the way the granules are bound. If in the first two mentioned technologies, powdered particles are processed without passing into the liquid phase (they heat up less, and sintering is the base) in the SLM process, more powerful lasers are used leading to the complete melting of the powder particles [ 1 , 2 , 3 , 7 , 8 , 9 ]. With the help of SLM technology, denser structures with better mechanical and surface characteristics are obtained due to the processing conditions and peculiarities, and the field of applicability is a wider one than in the case of other selective laser deposition technologies; but despite all this, the price of SLM equipment is generally higher than DMLS equipment, especially SLS equipment (which usually works with polymers or other non-metallic powders) [ 1 , 2 , 3 , 7 , 8 , 9 ].…”

“…If in the first two mentioned technologies, powdered particles are processed without passing into the liquid phase (they heat up less, and sintering is the base) in the SLM process, more powerful lasers are used leading to the complete melting of the powder particles [ 1 , 2 , 3 , 7 , 8 , 9 ]. With the help of SLM technology, denser structures with better mechanical and surface characteristics are obtained due to the processing conditions and peculiarities, and the field of applicability is a wider one than in the case of other selective laser deposition technologies; but despite all this, the price of SLM equipment is generally higher than DMLS equipment, especially SLS equipment (which usually works with polymers or other non-metallic powders) [ 1 , 2 , 3 , 7 , 8 , 9 ]. All equipment control is performed with the help of a process computer in which the digital model of the future printing structure is loaded.…”

“…This digital model is preprocessed in the software systems of the equipment in which sacrifice layers are created, scanning and selective processing trajectories are generated for all layers of the structure, important working parameters and specific processing parameters are set for processing a particular material, etc. [ 1 , 2 ]. Electron beam melting (EBM) is an additive processing method that belongs to the PBF category and has working principles similar to selective laser methods.…”

“…The additive technology used to produce the dental prostheses in this paper is the SLM method, which has spectacular strengths and advantages [ 1 , 2 , 3 , 8 , 9 , 24 , 25 , 26 , 27 ] and is integrated into many important applications and offers new horizons for improving efficiency and capabilities in various fields [ 28 , 29 , 30 ], especially the medical field [ 31 , 32 , 33 , 34 , 35 , 36 , 37 ] and the dental field [ 1 , 2 , 38 , 39 ]. Even if the performance of dental prostheses made by SLM technology is worthy of appreciation, there are obviously some disadvantages; for example, the condition of initially obtained surfaces that are rough and require post-processing operations to obtain the right surface quality for the application in which they are provided [ 1 , 2 , 8 , 9 , 27 ]. The problem related to the poor quality of the initial surfaces obtained by selective laser melting technology is solved and compensated with the help of finishing [ 40 ] and mechanical [ 41 ] or electrochemical polishing methods [ 42 ].…”