Influence of thermo-mechanical cycling on porcelain bonding to cobalt–chromium and titanium dental alloys fabricated by casting, milling, and selective laser melting

2018 ◽  
Vol 62 (2) ◽  
pp. 184-194 ◽  
Author(s):  
Maja Antanasova ◽  
Andraž Kocjan ◽  
Janez Kovač ◽  
Borut Žužek ◽  
Peter Jevnikar
Keyword(s):  
Selective Laser Melting ◽  
Dental Alloys ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Mechanical Cycling

Surface Formation Mechanisms in Selective Laser Melting of Cobalt-Chromium-Molybdenum Powder

2020 ◽  
Vol 839 ◽  
pp. 73-78
Author(s):  
Alexander A. Saprykin ◽  
Yuriy P. Sharkeev ◽  
Natalya A. Saprykina ◽  
Egor A. Ibragimov
Keyword(s):  
Selective Laser Melting ◽  
Marangoni Effect ◽  
Powdered Material ◽  
Formation Mechanisms ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Movement Velocity ◽  
Surface Formation ◽  
Preheating Temperature ◽  
Cobalt Chromium Molybdenum

Selective laser melting (SLM) is a manufacturing technology of metal parts of any shapes with target mechanical properties by means of laser melting. This paper discusses the effect of SLM parameters: laser output power, laser movement velocity, scanning pitch and preheating temperature of a powdered material on surface formation mechanism, namely, its physical configuration when melting cobalt-chromium-molybdenum powdered material Со28Cr3Mo. The study points at structural differences of melted surfaces even under identical process parameters. Several types of surface formation are identified, e.g. homogenous melt, coagulated particles, and shapeless particles. Vapor pressure, Marangoni effect, and heat effect of a melted powder are stated to be key reasons for rough surface. This research is of high importance for understanding the effect of SLM parameters on formation of a target quality surface, positive stability and repeatable accuracy of the process.

Mechanical Properties and Microstructural Characterization of Cobalt-Chromium (CoCr) Obtained by Casting and Selective Laser Melting (SLM)

2017 ◽  
Vol 899 ◽  
pp. 534-539 ◽  
Author(s):  
Marcello Vertamatti Mergulhão ◽  
Carlos Eduardo Podestá ◽  
Maurício David Martins das Neves
Keyword(s):  
Mechanical Properties ◽  
Selective Laser Melting ◽  
Rupture Strength ◽  
Chemical Properties ◽  
Optical Microscope ◽  
Tensile Yield Strength ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Standard Samples ◽  
Casting Technique

The aim of this study is the consolidation of Cobalt-Chromium (CoCr) alloy powder using the additive manufacturing - selective laser melting (SLM) and the investment casting techniques. The research of this study has been applied to their biomaterial applied to development of prosthesis and dental implants. The gas atomized powder are spherical (mean diameter equal to 42,74 μm) and was analyzed by their physical and chemical properties. The microstructure of the powder and specimens was evaluated using optical microscope (OM) and scanning electron microscope with energy-dispersed X-ray spectroscopy (SEM-EDS). The mechanical properties were evaluated of standard samples using a tensile (yield strength, maximum tensile, rupture tensile and elongation), three point bending (transverse rupture strength) and micro hardness tests. The mechanical results indicate higher values for the SLM than casting specimens. The micrographs revealed a characteristic morphology of laser been used in the SLM technique and the dendrites in the casting technique. The microstructure of samples made by SLM is thinner than the samples obtained in the cast.

scholarly journals Comparison of Marginal Integrity and Surface Roughness of Selective Laser Melting, CAD-CAM and Digital Light Processing Manufactured Co-Cr Alloy Copings

2021 ◽  
Vol 11 (18) ◽  
pp. 8328
Author(s):  
Abdulaziz S. Alqahtani ◽  
Abdullah M. AlFadda ◽  
Malek Eldesouky ◽  
Mazen K. Alnuwaiser ◽  
Samar Al-Saleh ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Digital Light Processing ◽  
Group 4 ◽  
Cad Cam ◽  
Ct Analysis ◽  
Group 3 ◽  
Group 2 ◽  
Cast Technique

The purpose of the present study was to evaluate the influence of fabrication techniques on the surface micro-roughness (Ra) and marginal misfit of cobalt chromium (CoCr) copings. A mandibular first molar was prepared for a metal ceramic crown. Forty metal copings were prepared and divided into groups (n = 10). Group 1, Casting-Lost wax technique (Cast-LWT), Group 2, CAD-CAM, Group 3, Selective laser melting (SLM), and Group 4, Digital light processing-Cast (DLP-Cast). Ra was measured using laser profilometry and marginal misfit was analyzed with Micro-CT. Analysis of variance (ANOVA), Tukey multiple comparison, and correlation coefficient tests were applied (p < 0.05). SLM technique showed the highest Ra (2.251 ± 0.310 μm) and the Cast-LWT group presented the lowest Ra (1.055 ± 0.184 μm). CAD-CAM copings showed statistically lower Ra compared with SLM samples (p = 0.028), but comparable Ra to DLP-Cast (p > 0.05). CoCr copings fabricated from the DLP-Cast technique demonstrated the highest marginal misfit (147.746 ± 30.306 μm) and the lowest misfit was established by SLM copings (27.193 ± 8.519 μm). The SLM technique displayed lower marginal misfit than DLP-Cast and CAD-CAM (p = 0.001), but comparable misfit to Cast-LWT copings. Ra influenced the marginal misfit in CAD-CAM, SLM, and DLP-Cast technique-fabricated copings. (p < 0.01). Marginal misfit and Ra of CoCr copings are contingent on the different fabrication techniques.

Study on Selective Laser Melting Forming Process of Cobalt Chromium Alloy

2015 ◽  
Vol 42 (5) ◽  
pp. 0503001
Author(s):  
刘威 Liu Wei ◽  
刘婷婷 Liu Tingting ◽  
廖文和 Liao Wenhe ◽  
蒋立异 Jiang Liyi
Keyword(s):  
Selective Laser Melting ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Forming Process ◽  
Cobalt Chromium Alloy

Selective Laser Melting Forming Hardness Rule of Cobalt Chromium Alloy and its Prediction Model

2016 ◽  
Vol 43 (3) ◽  
pp. 0303007
Author(s):  
刘婷婷 Liu Tingting ◽  
廖文和 Liao Wenhe ◽  
张凯 Zhang Kai ◽  
刘威 Liu Wei
Keyword(s):  
Prediction Model ◽  
Selective Laser Melting ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Cobalt Chromium Alloy

Simulating Melt Pool Shape and Lack of Fusion Porosity for Selective Laser Melting of Cobalt Chromium Components

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Chong Teng ◽  
Haijun Gong ◽  
Attila Szabo ◽  
J. J. S. Dilip ◽  
Katy Ashby ◽  
...  
Keyword(s):  
Selective Laser Melting ◽  
Defect Formation ◽  
Powder Layer ◽  
Complex Object ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Design Modification ◽  
Lack Of Fusion ◽  
Melt Pool ◽  
Geometrically Complex

Cobalt chromium is widely used to make medical implants and wind turbine, engine and aircraft components because of its high wear and corrosion resistance. The ability to process geometrically complex components is an area of intense interest to enable shifting from traditional manufacturing techniques to additive manufacturing (AM). The major reason for using AM is to ease design modification and optimization since AM machines can directly apply the changes from an updated STL file to print a geometrically complex object. Quality assurance for AM fabricated parts is recognized as a critical limitation of AM processes. In selective laser melting (SLM), layer by layer melting and remelting can lead to porosity defects caused by lack of fusion, balling, and keyhole collapse. Machine process parameter optimization becomes a very important task and is usually accomplished by producing a large amount of experimental coupons with different combinations of process parameters such as laser power, speed, hatch spacing, and powder layer thickness. In order to save the cost and time of these experimental trial and error methods, many researchers have attempted to simulate defect formation in SLM. Many physics-based assumptions must be made to model these processes, and thus, all the models are limited in some aspects. In the present work, we investigated single bead melt pool shapes for SLM of CoCr to tune the physics assumptions and then, applied to the model to predict bulk lack of fusion porosity within the finished parts. The simulation results were compared and validated against experimental results and show a high degree of correlation.

scholarly journals An Experimental Study on Micro-Milling of a Medical Grade Co-Cr-Mo Alloy Produced by Selective Laser Melting

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2208 ◽  
Author(s):  
Gabriele Allegri ◽  
Alessandro Colpani ◽  
Paola Serena Ginestra ◽  
Aldo Attanasio
Keyword(s):  
Additive Manufacturing ◽  
Selective Laser Melting ◽  
Chip Thickness ◽  
Material Behavior ◽  
Micro Milling ◽  
Cobalt Chromium ◽  
Laser Melting ◽  
Chip Formation Mechanism ◽  
Manufacturing Techniques ◽  
Cobalt Chromium Molybdenum

Cobalt-chromium-molybdenum (Co-Cr-Mo) alloys are very promising materials, in particular, in the biomedical field where their unique properties of biocompatibility and wear resistance can be exploited for surgery applications, prostheses, and many other medical devices. While Additive Manufacturing is a key technology in this field, micro-milling can be used for the creation of micro-scale details on the printed parts, not obtainable with Additive Manufacturing techniques. In particular, there is a lack of scientific research in the field of the fundamental material removal mechanisms involving micro-milling of Co-Cr-Mo alloys. Therefore, this paper presents a micro-milling characterization of Co-Cr-Mo samples produced by Additive Manufacturing with the Selective Laser Melting (SLM) technique. In particular, microchannels with different depths were made in order to evaluate the material behavior, including the chip formation mechanism, in micro-milling. In addition, the resulting surface roughness (Ra and Sa) and hardness were analyzed. Finally, the cutting forces were acquired and analyzed in order to ascertain the minimum uncut chip thickness for the material. The results of the characterization studies can be used as a basis for the identification of a machining window for micro-milling of biomedical grade cobalt-chromium-molybdenum (Co-Cr-Mo) alloys.

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