• Journal of Dental Rehabilitation and Applied Science
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• v.32 no.3
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• pp.246-254
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• 2016

Nowadays, 3 dimentional (3D) printing, especially Direct Metal Laser Sintering (DMLS) system is used in dentistry. DMLS system has recently been introduced for fabrication metal framework for metal ceramic crowns to overcome the disadvantages of the casting method and computer aided design/computer aided manufacturing (CAD/CAM) milling system. DMLS system uses a high-temperature laser beam to selectively heat a substructure metal powder based on the CAD data with the framework design. A thin layer of the beamed area becomes fused, and the metal framework is completed by laminating these thin layers. Utilizing DMLS system to fabricate fixed prostheses is expected to achieve free-from shaping without mold and limitations from cutting tools, fabricate prostheses with complex geometry, prevent distortion and fabrication defects that inherent to conventional fabrication methods. The purpose of this case report is to demonstrate various fixed prostheses such as long span fixed prostheses, post to achieve satisfactory results in functional and esthetic aspects.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.250-251
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• 2006

It is known that powder characteristics including particle size and distribution, particle shape, and chemical composition are important parameters which influence direct laser sintering of metal powders. In this paper, we introduce a first order kinetics model for densification of steel powders during laser sintering. A densification coefficient (K) is defined which express the potential of different powders to be laser-sintered to a high density dependent on their particle characteristics.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.248-249
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• 2006

Direct Metal Laser Sintering (DMLS) has been utilized for prototype manufacturing of functional metal components for years now. During this period the surface quality, mechanical properties, detail resolution and easiness of the process have been improved to the level suitable for direct production of complex metallic components for various applications. The paper will present the latest DMLS technology utilizing EOSINT M270 laser sintering machine and EOSTYLE support generation software for direct and rapid production of complex shaped metallic components for various purposes. The focus of the presentation will be in rapid manufacturing of customized biomedical implants and surgical devices of the latest stainless steel, titanium and cobalt-chromium-molybdenum alloys. In addition to biomedical applications, other application areas where complex metallic parts with stringent requirements are being needed will be presented.

• Journal of Technologic Dentistry
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• v.42 no.2
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• pp.81-89
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• 2020

Purpose: This in vitro study was conducted to evaluate the marginal and internal fit of three-unit Co-Cr frameworks fabricated by computer-aided metal milling and direct metal laser sintering(DMLS) systems in comparison to conventional casting method. Methods: Three-unit Co-Cr frameworks were fabricated by conventional wax up with casting(CWC), computer-aided metal milling(MM) and direct metal laser sintering(DMLS)(n=10 each). The marginal and internal fit of specimens were examined using a light-body silicone impression material. The thickness of light-body silicone was measured at eight reference points each, divided in the mesio distal and bucco lingual directions. All measurements were conducted by a stereomicroscope. Digital photos were taken at 150× magnification and then analyzed using a measurement software. The Kruskal-Wallis test and Bonferroni correction were used for analyzing the results. Results: The mean(SD) is ㎛ for fabrication methods, the mean marginal fit were recorded respectively, DMLS 39(27), followed by CWC 63(38), MM 220(128). and the mean internal fit CWC 95(47), DMLS 116(49), MM 210(152). In addition, the largest gap was found in the occlusal surface area among the internal measurement areas of all groups. Conclusion: As a result, the direct metal laser sintering method showed better marginal and internal fit than the metal milling method. The marginal and internal fit were statistically different according to the three fabrication methods(p<0.001). Except the MM group, the marginal fit of the CWC and DMLS groups was below the clinical standard of 120 ㎛. Based on the results of this study, it can be applied to clinical use in the future.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.251-256
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• 2020

In recent years, digital technology has been developed in dentistry, which denture frameworks can be manufactured using DMLS (Direct Metal Laser Sintering) technique. A traditional impression method can be replaced by oral scanning and wax pattern production process can be achieved by the use of CAD/CAM techniques. The designed STL files can be sent to DMLS devices to fabricate final components of removable partial dentures (RPD). The advantages of digital dentistry are concision and precision. In this case study, a fracture of occlusal rests providing support and indirect retention was repaired by DMLS and laser welding techniques. It shows satisfactory results in adaptation accuracy and functional properties of the repaired denture.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.7
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• pp.1-9
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• 2022

Peeling and dimensional deformation that occur during a manufacturing process are accompanied by an increase in the manufacturing cost and production time caused by manufacturing defects. In order to solve this problem, it is essential to predict risk factors at the design stage through computational analysis of the additive manufacturing process and to control shape distortion due to residual stress. In this study, the dimensional characteristics were improved by applying the distortion compensation design through computational analysis to minimize the distortion occurring in the DMLS(Direct Metal Laser Sintering) method of the metal additive manufacturing process.

• Design & Manufacturing
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• v.9 no.3
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• pp.34-40
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• 2015

In the study, Three-dimensional drawing parts for conformal cooling circuit cavity & core and their 3D Metal parts using DMLS(Direct MetalLaser Sintering) and NC integrated machining center were showned. For conformal cooling circuit cavity and core parts, I discussed its practicality to DMLS multiple machinins process introducing general manufacturing process and comparing with them.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.552-556
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• 1997

The Direct Metal Prototyping(DMP), one of the rapid prototyping technologies, allows the manufacturing of three-dimensional metallic parts using metal powders directly from the CAD data. Laser power and scanning speed are the most important variables of the process. The objective of this study is to obtain the design data for laser power and scanning speed to bond metal powders effectively using the finite element method. To obtain the design values, a numerical analysis considering two-dimensional heat transfer during the sintering of metal powder layers of the process was performed. The laser beam has been modeled to have directionality in its heat flux distribution, i. e., in the scanning direction a Gaussian beam mode distribution has been assumed and in the thickness direction a square beam mode distribution. The three-dimensional irregular distribution of metal powders of the powder layer is idealized as two-dimensional distribution in which metal powders are located regularly and periodically on the plate. In this study the design values of laser power vs scanning speed have been obtained. Temperature distribution and temperature variation of the powder layers with respect to time have been predicted. The commputed dsign data will be useful in determining the initial conditions of the process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.193-194
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• 2006

• The Journal of Korean Academy of Prosthodontics
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• v.57 no.4
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• pp.350-355
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• 2019

For the success of complete denture, three essential requirements such as retention, stability and support are needed. Moreover, due to the absorption of residual ridge and scarring due to the surgery, when making a complete denture, which is difficult to form the mandibular lingual margins, various considerations such as the arrangement of the Non-anatomical dl non-anatomical teeth, the polished surface impression, the internally weighted metal framework and the use of the denture adhesive cream are necessary. In this case report, the patient has a severely resorbed edentulous ridge from severe periodontitis and has some soft tissue problems after the glossectomy due to tongue cancer. To obtain additional retention and stability, some trials such as polished surface impression taking, internally weighted metal insertion and minimal pressure impression were done for the better result. Moreover To make a metal framework that precisely shapes the desired three-dimensional shape and reduces the complicated process, minimal pressure impression method and direct metal laser sintering technique were used.