• 한국기계가공학회지
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• 제20권1호
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• pp.66-73
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• 2021

In this paper, we analyzed and considered the precision of parts produced by 3D printing methods. For the latch systems applied to the Wingline folding doors, the 3D shape of the door hinge part was printed using FDM and DLP methods. Then, the 3D printed shape was scanned to measure the dimensions and dimensional changes of the actual model. In the comparison and analysis of the 3D printed door hinge parts, because the output filling density is 100% owing to the characteristics of DLP 3D printing, the filling density in FDM 3D printing was also set to 100%.

• 한국분말재료학회지
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• 제30권4호
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• pp.318-323
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• 2023

The thermoelectric effect, which converts waste heat into electricity, holds promise as a renewable energy technology. Recently, bismuth telluride (Bi2Te3)-based alloys are being recognized as important materials for practical applications in the temperature range from room temperature to 500 K. However, conventional sintering processes impose limitations on shape-changeable and tailorable Bi₂Te₃ materials. To overcome these issues, three-dimensional (3D) printing (additive manufacturing) is being adopted. Although some research results have been reported, relatively few studies on 3D printed thermoelectric materials are being carried out. In this study, we utilize extrusion 3D printing to manufacture n-type Bi_1.7Sb_0.3Te₃ (N-BST). The ink is produced without using organic binders, which could negatively influence its thermoelectric properties. Furthermore, we introduce graphene oxide (GO) at the crystal interface to enhance the electrical properties. The formed N-BST composites exhibit significantly improved electrical conductivity and a higher Seebeck coefficient as the GO content increases. Therefore, we propose that the combination of the extrusion 3D printing process (Direct Ink Writing, DIW) and the incorporation of GO into N-BST offers a convenient and effective approach for achieving higher thermoelectric efficiency.

• 한국기계가공학회지
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• 제14권4호
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• pp.62-72
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• 2015

Interest in three-dimensional (3D) printing processes has grown significantly, and several types have been developed. These 3D printing processes are classified as Selective Laser Sintering (SLS), Stereo-Lithography Apparatus (SLA), and Fused Deposition Modeling (FDM). SLS can be applied to many materials, but because it uses a laser-based material removal process, it is expensive. SLA enables fast and precise manufacturing, but available materials are limited. FDM printing's benefits are its reasonable price and easy accessibility. However, metal printing using FDM can involve technical problems, such as suitable component supply or the thermal expansion of the heating part. Thus, FDM printing primarily uses materials with low melting points, such as acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA) resin. In this study, an FDM process for enabling metal printing is suggested. Particularly, the nozzle and heatsink for this process are focused for stable printing. To design the nozzle and heatsink, multi-physical phenomena, including thermal expansion and heat transfer, had to be considered. Therefore, COMSOL Multiphysics, an FEM analysis program, was used to analyze the maximum temperature, thermal expansion, and principal stress. Finally, its performance was confirmed through an experiment.

• 대한기계학회논문집A
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• 제41권9호
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• pp.839-844
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• 2017

최근 3차원 프린팅 기술은 비약적으로 발전하여 쾌속조형기술의 대명사가 되고 있다. FDM 방식의 3D프린터는 쾌속조형에 사용되는 가장 일반적인 프린터이지만, 열에 취약하고, 출력물의 표면이 매끄럽지 못하는 등의 문제를 가지고 있다. 본 논문에서는 FDM방식의 3D프린터로 ABS재질의 시편을 제작하였고, 아세톤에 시편을 담그는 방식으로 후처리를 수행하였다. 공정시간을 변수로 후처리를 진행하였으며, 처음 5초의 후처리 시간동안에는 시편의 표면조도가 급격하게 개선되는 결과를 획득하였으며, 5초 이후에는 표면조도의 변화정도가 미미하였다. 또한, 이러한 후처리 공정은 적지만 시편의 인장강도와 파단변형률을 상승시키는 결과를 나타내었다.

• 융합정보논문지
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• 제10권10호
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• pp.47-52
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• 2020

일반적인 평판 프린터 시스템은 PC와 전용 S/W로 구성되어 사용에 불편함이 존재한다. 결국, 평판 프린터 시스템 구성의 간소화, 스마트화 등을 통해 다양한 형태의 프린팅을 쉽고 편리하게 사용할 수 있는 기술이 필요하다. 즉, 한 대의 프린터로 여러 종류의 소재에 인쇄가 가능하며, 다양한 형태의 상품을 인쇄할 수 있는 다입체 프린터에 대한 수요가 증가하고 있다. 따라서, 본 논문에서는 Head Encoder/Trigger 제어를 이용하여 다입체 인쇄가 가능한 평판 프린터 시스템을 개발하였다. 이를 위해, 평판 프린터 내부 모듈을 입력 형태 감지 센서를 연계시키고, 별도의 메인 콘트롤러를 통해 프린터의 Head Encoder와 Head Trigger 신호에 의해 모든 동작 상태를 제어하는 평판 프린터를 개발하였다. 이를 통해, IoT 기술의 발전 및 보급의 확산으로 산업 전반에 걸쳐 스마트 환경의 프린터 제어가 발전된 형태로 확대될 것이며, 향후 3D 프린팅 산업 발전에 기여할 것으로 기대된다.

• 대한치과교정학회지
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• 제45권5호
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• pp.217-225
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• 2015

Objective: Three-dimensional (3D) printing is a recent technological development that may play a significant role in orthodontic diagnosis and treatment. It can be used to fabricate skull models or study models, as well as to make replica teeth in autotransplantation or tooth impaction cases. The aim of this study was to evaluate the accuracy of fabrication of replica teeth made by two types of 3D printing technologies. Methods: Fifty extracted molar teeth were selected as samples. They were scanned to generate high-resolution 3D surface model stereolithography files. These files were converted into physical models using two types of 3D printing technologies: Fused deposition modeling (FDM) and PolyJet technology. All replica teeth were scanned and 3D images generated. Computer software compared the replica teeth to the original teeth with linear measurements, volumetric measurements, and mean deviation measurements with best-fit alignment. Paired t-tests were used to statistically analyze the measurements. Results: Most measurements of teeth formed using FDM tended to be slightly smaller, while those of the PolyJet replicas tended to be slightly larger, than those of the extracted teeth. Mean deviation measurements with best-fit alignment of FDM and PolyJet group were 0.047 mm and 0.038 mm, respectively. Although there were statistically significant differences, they were regarded as clinically insignificant. Conclusions: This study confirms that FDM and PolyJet technologies are accurate enough to be usable in orthodontic diagnosis and treatment.

• Design & Manufacturing
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• 제12권3호
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• pp.19-24
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• 2018

Fused deposition Modeling (FDM) is one of the most widely used for the prototype of parts at ease. The FDM 3D printing method is a lamination manufacturing method that the resin is melted at a high temperature and piled up one by one. Another term is also referred to as FFF (Fused Filament Fabrication). 3D printing technology is mainly used only in the area of prototype production, not in production of commercial products. Therefore, if FDM 3D printer is applied to the product process of commercial products when considered, the strength and dimensional accuracy of the manufactured product is expected to be important. In this study, the mechanical properties of parts made by 3D printing with FDM method were investigated. The aim of this work is to examine how the mechanical properties of the FDM parts, by changing of processing FDM printing direction and the height of stacking layer is affected. The effect of the lamination direction and the height of the stacking layer, which are set as variables in the lamination process, by using the tensile specimen and impact specimen after the FDM manufacturing process were investigated and analyzed. The PLA (Poly Lactic Acid) was used as the filament materials for the 3D printing.

• 한국기계가공학회지
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• 제15권2호
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• pp.38-45
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• 2016

Since a 5-axis machine tool has two rotary axes, it offers numerous advantages, such as flexible accessibility, longer tool life, better surface finish, and more accuracy. Moreover, it can conduct whole machining by rotating the rotary feed axes while setting the fixture at once without re-fixing in contrast to conventional 3-axis machining. However, it is difficult to produce complicated products that have a hollow shape. In contrast, 3D printing can produce an object with a complicated hollow shape easily and rapidly. However, because of layer thickness and shrinkage, its surface finish and dimensional accuracy are not adequate. Therefore, this study proposes hybrid technology by integrating the advantages of these two manufacturing processes. 3D printing was used as the additive manufacturing rapidly in the whole body, and 5-axis machining was used as the subtractive manufacturing accurately in the joining and driving places. The reliability of the proposed technology was verified through a comparison with conventional technology in the aspects of processing time, surface roughness. and dimensional accuracy.

• 한국임상수의학회지
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• 제39권5호
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• pp.246-252
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• 2022

Multilobular osteochondrosarcoma (MLO) reportedly has a good prognosis after complete resection. This study reports the successful treatment of MLO in two dogs using 3-dimensional (3D) printing technology. A nine-year-old castrated male Maltese (Case 1) and a five-year-old castrated male poodle (Case 2) both presented with a mass in the skull. Diagnostic imaging revealed a cranial mass arising from the cranio-orbital and parieto-occipital bones. The masses were resected using 3D-printed osteotomy guides, and the resulting defects were reconstructed using 3D-printed patient-specific implants. Histopathological results confirmed the resection of MLOs with clean margins. Patients routinely recover from surgery without complications. To date, the two patients remain alive without clinical signs of tumor recurrence at 20 and 12 months postoperatively, respectively. In the management of MLO in dogs, 3D printing technology can allow accurate tumor resection, reduced surgical time, and successful reconstruction of large defects.

• 패션비즈니스
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• 제24권4호
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• pp.130-143
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• 2020

The development of three-dimensional (3D) printing technology is bringing new innovations to various fields such as health care, architecture, and fashion. 3D printing can be manufactured to suit the size of the consumer's body, modify the design to meet their tastes, and produce small quantities of various products. Therefore, 3D printing in the field of fashion has great potential. The purpose of this study was to investigate various application models of 3D printing for fashion design and analyze their characteristics after developing the fashion garment samples. First, the background of 3D printing was reviewed then, fashion designed by a 3D printing application was analyzed. As a result, four types of 3D printing applications were developed: object-attached, linkage, kinematics, and assembly. The object-attached type was the method of printing 3D material as an object in the intended shape and form and was attached to the garment by sewing. The linkage type referred to printing 3D material in small pieces of certain shapes that could be linked. The kinematics type was structures with hinges that could flex to fit the human body. The assembly type referred to developing 3D materials in female and male pieces such as nuts and bolts. By providing the advantages, disadvantages, trial-and-errors, and challenges of the 3D printing fashion design process, this study contributes to the effective applications and possibilities of future design.