• 대한방사선기술학회지:방사선기술과학
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• 제46권2호
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• pp.151-157
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• 2023

The purpose of this study was to develop an assist device that could correct and support patient position during biopsy on computed tomography (CT) using 3D printing technology. The development method was conducted in the order of 3D design, 3D output, intermediate evaluation for product, final assist device evaluation. The 3D design method was conducted in the order of prior research data survey, measurement, primary modeling, 3D printing, output evaluation, and supplementary modeling. The 3D output was the 3D printer (3DWOX 2X, Sindoh, Korea) with additive manufacturing technology and the polylactic acid (PLA) materials. At this time, the optimal strength was evaluated to infill degree of product as the 3D printing factors into 20%, 40%, 60%, and 80%. The intermediate evaluation and supplementation was measured noise in the region of interest (ROI) around the beam hardening artifact on the CT images. We used 128-channel MDCT (Discovery 75 HD, GE, USA) to scan with a slice thickness of 100 kVp, 150 mA, and 2.5 mm on the 3D printing product. We compared the surrounding noise of the final 3D printing product with the beginning of it. and then the strength of it according to the degree of infill was evaluated. As a result, the surrounding noise of the final and the early devices were measured at an average of 3.3 ± 0.5 HU and 7.1 ± 0.1 HU, respectively, which significantly reduced the noise of the final 3D printing product (p<0.001). We found that the percentage of infill according to the optimal strength was found to be 60%. Finally, development of assist devices for CT biopsy will be able to minimize artifacts and provide convenience to medical staff and patients.

• 드라이브 ㆍ 컨트롤
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• 제16권3호
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• pp.42-50
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• 2019

3D printing AM processes have advantages in complex shapes, customized fabrication and prototype development stage. However, due to various parameters based on both the machine and the material, the AM process can produce finished output after several trials and errors in the initial stage. As such, minimizing or optimizing negative factors for various parameters of the 3D printing AM process could be a solution to reduce the trial-and-error failures in the early stages of such an AM process. In addition, this can be largely solved through software simulation in the preprocessing process of 3D printing AM process. Therefore, the objective of this study was to investigate a simulation technology for the AM software, especially Ansys Inc. The metal 3D printing AM process, the AM process simulation software, and the AM process simulation processor were examined. Through this study, it will be helpful to understand 3D printing AM process and AM process simulation processor.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.116-117
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• 2019

3D printing technology can be applied to various industries, and is trapped by major technologies that change existing manufacturing processes. 3D printing materials must satisfy designability, economy and productivity, and building materials are required to have strength and economy secured technology. 3D printing technology of construction field can be divided into structural materials and internal and external materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a lamination type, and the role of a cement base composite material is important. In this research, we developed a cementitious base binder applicable as a 3D printing exterior materials, confirmed high temperature strength characteristics for application as an exterior materials of buildings and confirmed its possibility.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.65-66
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• 2022

In the construction industry, interest in technologies such as 3D Construction Printing (3DCP) is increasing, and research is being conducted continuously. In the case of atypical architecture, different shapes must be implemented, and the introduction of 3D printing technology is intended to solve it. Our researchers are conducting research to produce Free-form Concrete Panel (FCP). It automatically manufactures the FCP's formwork without any error with the design shape. At this time, the concrete nozzle based on the 3D printing technology is developed and the concrete is precisely extruded into the manufactured form to prevent the deformation of the formwork that can occur due to the concrete load. Therefore, in this study, the requirements for the development of 3D printing concrete nozzles for FCP manufacturing are analyzed. Based on the analyzed requirements, the first nozzle was developed. Such equipment is easy to shorten construction period and cost reduction in the atypical construction field, and is expected to be utilized as basic 3D printing equipment.

• 대한치과기공학회지
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• 제43권1호
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• pp.13-18
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• 2021

Purpose: This study aimed to compare the flexural properties and perform the Weibull analysis of photo-curing three-dimensional (3D) printing resin. Methods: Photo-curing temporary resin (3D polymer) was used as a printing resin. Specimens (65 × 10 × 3.3 ㎣) were prepared following the ISO 20975-1 guidelines and according to the different printing orientations using a digital light processing 3D printer (D2 120; Dentium). The flexural strength (FS), flexural modulus, and work of fracture (WOF) were measured using a universal testing machine (Instron 3344; Instron) at a crosshead speed of 5 mm/min. Results: In this study, the 0° orientation exhibited higher FS and WOF than the 45° orientation. Significant differences were found among the printing orientations (p<0.05). Specimens printed at the 0° orientation were the most accurate. In the Weibull analysis, 0° showed the greatest Weibull modulus (m), which represents a higher reliability. Conclusion: 3D printing should be selected and used by considering flexural properties, size accuracy, and reliability.

• 한국산업보건학회지
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• 제30권2호
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• pp.153-162
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• 2020

Objectives: 3D printing technologies have become widely developed and are increasingly being used for a variety of purposes. Recently, the evaluation of 3D printing operations has been conducted through chamber test studies, and actual workplace studies have yet to be completed. Therefore, the objective of this study was to determine the emission of volatile organic compounds(VOCs), metals, and particles from printing operations at a workplace. This included monitoring conducted at a commercial 3D printing service workplace where the processes involved material extrusion, material jetting, binder jetting, vat photo polymerization, and powder bed fusion. Methods: Area samples were collected with using a Tenax TA tube for VOC emission and MCE filter for metals in the workplace. For particle monitoring, Mini Particle Samplers(MPS) were also placed in the printer, indoor work area, and outdoor area. The objective was to analyze and identify particles' size, morphology, and chemical composition using transmission electron microscopy with energy dispersive spectroscopy(TEM-EDS) in the workplace. Results: The monitoring revealed that the concentration of VOCs and metals generated during the 3D printing process was low. However, it also revealed that within the 3D printing area, the highest concentration of total volatile organic compounds(TVOC) was 4,164 ppb at the vat photopolymerization 3D printing workplace, and the lowest was 148 ppb at the material extrusion 3D printing workplace. For the metals monitoring, chromium, which, is carcinogenic for humans, was detected in the workplace. As a characteristic of the particles, nano-sized particles were also found during the monitoring, but most of them were agglomerated with large and small particles. Conclusions: Based on the monitoring conducted at the commercial 3D printing operation, the results revealed that the concentration of VOCs and metals in the workplace were within Korea's occupational exposure limits. However, due to the emission of nano-sized particles during 3D printing operations, it was recommended that the exposure to VOCs and metals in the workplace should be minimized out of concern for workers' health. It was also shown that the characteristics of particles emitted from 3D printing operations may spread widely within an indoor workplace.

• 한국기계가공학회지
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• 제14권6호
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• pp.142-148
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• 2015

3D printing technology is a promising technique for fabricating complex 3D architectures based on the CAD/CAM system, and it has been extensively investigated to manufacture structures in the fields of mechanical engineering, space technology, automobiles, and biomedical and electrical applications. Recent advances in the 3D printing of soft structures have received attention for the application of the construction of flexible sensors of soft robotics or the recreation of tissue/organ-specific microenvironments. In this review paper, we would like to focus on delivering state-of-the-art fabrication of soft structures with 3D printing technology and its various applications.

• 소성∙가공
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• 제31권2호
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• pp.89-95
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• 2022

3D printing products manufactured by material extrusion are used in many industrial fields recently. However, these products are difficult to use in the field due to their low tensile strengths. In order to solve this problem, research on improving the tensile strength of the output using a 3D printer has been continuously conducted. In this study, we performed a tensile test using Universal Testing Machine according to infill pattern, nozzle temperature, bed temperature, and printing speed conditions. Results revealed that tensile specimen of concentric shape had the highest tensile strength in infill pattern condition and that the tensile strength increased linearly with increasing nozzle and bed temperatures. However, the tensile strength decreased with increasing printing speed. Consequently, we confirmed that tensile strength could be increased and decreased depending on output conditions of 3D printing.

• 한국전자통신학회논문지
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• 제16권5호
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• pp.909-916
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• 2021

3D 프린터는 개인의 창의력을 실제로 구현할 수 있는 장점이 있다. 이 특성을 활용하려는 사람들은 증가하고 있지만 적합한 프린팅 교육의 기회 부족과 잘못된 출력 방법으로 문제 발생의 어려움을 겪는다. 따라서 저하된 출력물 품질이 사용자의 관심을 낮춰 점차 3D 프린터의 활용빈도 수를 감소시키게 된다. 본 연구에서는 3D 프린터의 오작동 해결과 편의성의 개선을 위해 직접 기기를 작동하면서 발생하는 문제를 파악하고 분석했다. 여러 문제점 중 안착 불량, 스트링 현상, 노즐 막힘을 중점으로 해결과 완화 연구를 진행하였다. 또한, 3D 프린터의 기능을 실험을 통해 재료소모량 감소와 출력시간 단축 방법을 고찰했다. 최종적으로 3D 프린팅 중 빈번하게 발생하는 출력문제를 해결해 외관이 온전한 출력물을 얻을 수 있었고 편의성을 개선하였다.

• 한국융합학회논문지
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• 제10권4호
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• pp.189-194
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• 2019

본 논문은 산업전반에 빠르게 도입되어가고 있는 3D프린팅 기술을 이용하여 주얼리 디자인에 적용하기 위해 시작되었다. 선행연구를 살펴본 결과 디자인 분야에서는 3D출력 방식중 FMD방식이 가장 많이 사용되고 있었다. 하지만 주얼리 디자인에서는 3D프린팅은 제작과정 중 주조 과정에 사용되고 있어 출력방식이 FMD가 아닌 DLP방식을 사용하고 있다. 따라서 연구자는 DLP방식의 3D프린팅을 활용하여 주얼리 디자인에 응용함으로서 주얼리 디자인의 재료적 기능과, 활용 가능성에 대해 연구 작품을 통해 알아보았다. 그 결과 3D프린팅 출력 후 주조과정 없이 주얼리 디자인에 응용하고 에나멜, 정은 등을 함께 활용하여 브로치를 완성함으로서 가볍고 단단하며 다양한 색상의 완성품을 제작하여 적용 가능한 재료임을 알 수 있었다. 또한 기하학 구조가 아닌 주얼리 디자인에서 주로 사용되는 곡선적 디자인을 Rhino CAD로 크기와 형태를 정확히 예측할 수 있어 향후 주얼리 디자인 조형 형태 전개에 쉽게 활용할 수 있는 다양한 발전 가능성을 엿 볼 수 있었다.