• 대한심미치과학회지
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• 제27권2호
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• pp.82-96
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• 2018

3D 프린팅은 삼차원 이미지 정보를 이용하여 레이어로 분할한 후 선택한 소재를 적층하여 가공하는 방법을 말한다. 소재를 적층하는 방법에 따라 다양한 종류의 3D 프린팅이 존재하는데 최근 치과분야에서는 SLA방식과 DLP방식으로 광원을 이용한 경화를 통해 적층 가공하는 3D 프린팅이 널리 보급되어 사용되고 있다. 전악 범위의 3D프린팅 치과용 모델은 전통적인 인상 채득으로 제작된 스톤모델보다는 다소 정확성이 부족한 것으로 보고되었으나, 같은 STL파일을 이용하여 4분악 범위를 3D 프린팅한 모델은 밀링 방법으로 가공한 모델보다 정확하였다. 디자인 소프트웨어의 활용도에 따라 보철치료의 진단, 임시 보철물의 제작, 의치의 제작이 가능하였다. 교정에서는 투명 교정 모델과 브라켓 간접 부착을 위한 트레이 제작이 가능하였다. 임플란트 수술에 있어서 CT를 기반으로 한 정확한 위치에 임플란트를 식립하는 가이드 제작에 활용하고 있다. 출력 방식의 발전으로 인하여 3D 프린터의 출력시간이 계속적으로 단축되고 있으며, 이로 인해 치과 진료실 내에서 3D 프린터가 기존의 전통적인 가공 방법을 대체할 수 있을 것으로 기대한다.

• Journal of Computational Design and Engineering
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• 제2권4호
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• pp.253-260
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• 2015

Feature-based NC machining, which requires high quality of 3D CAD model, is widely used in machining aircraft structural part. However, there has been little research on how to automatically detect the CAD model errors. As a result, the user has to manually check the errors with great effort before NC programming. This paper proposes an automatic CAD model errors detection approach for aircraft structural part. First, the base faces are identified based on the reference directions corresponding to machining coordinate systems. Then, the CAD models are partitioned into multiple local regions based on the base faces. Finally, the CAD model error types are evaluated based on the heuristic rules. A prototype system based on CATIA has been developed to verify the effectiveness of the proposed approach.

• 한국기계가공학회지
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• 제15권4호
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• pp.118-124
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• 2016

In this paper, the model to develop the forming process for turbine seal is suggested. And numerical approach for the shape design of the turbine seal is examined. Because of the thin thickness of the turbine seal, the seal is easily fractured in the manufacturing process. The main factors of the seal manufacturing consist of addendum angle and dedendum angle, fillet on the addendum face, number of the gear teeth, sheet initial location and gear initial location, rake and vertical clearance. The structure and shape of seal are modeled using the commercial 3D mechanical design program, CATIA(V5/R20). Also, rolling process to manufacture the turbine seal is analyzed using DEFORM$^{TM}$-3D(V11), commercial forming analysis software and runs under PC workstation. This study focused on the shape design of turbine seal. Through this research, the main factors to make the turbine seal for airplane turbine engine can be obtained. This study results are reflected to the shape design for turbine seal.

• Design & Manufacturing
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• 제14권3호
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• pp.1-7
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• 2020

This paper predicts the mass and the length of injection-molded products through the Artificial Neural Network (ANN) method. The ANN was implemented with 5 input parameters and 2 output parameters(mass, length). The input parameters, such as injection time, melt temperature, mold temperature, packing pressure and packing time were selected. 44 experiments that are based on the mixed sampling method were performed to generate training data for the ANN model. The generated training data were normalized to eliminate scale differences between factors to improve the prediction performance of the ANN model. A random search method was used to find the optimized hyper-parameter of the ANN model. After the ANN completed the training, the ANN model predicted the mass and the length of the injection-molded product. According to the result, average error of the ANN for mass was 0.3 %. In the case of length, the average deviation of ANN was 0.043 mm.

• 한국기계가공학회지
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• 제21권8호
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• pp.72-78
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• 2022

Bending using high-frequency induction heating is used to bend pipes and sections, and is currently widely applied in industrial fields such as power generation facilities, ships, onshore plants, and offshore plants. The purpose of this study is to study the manufacturing process and design technology of high-frequency bending of pipe to make the best pipe design arrangement. Although various studies are being conducted in the field of high-frequency bending, more research is needed on high-frequency bending of pipes for ship building and offshore plants. The purpose of this study is to review the feasibility of production design using 3D model tool of S3D and AM(PDMS), and to review and improve bending thickness reduction, reduction rate, and roundness.

• 공업화학
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• 제34권5호
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• pp.522-528
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• 2023

반도체 제조공정인 다이싱 공정용 점착 테이프를 제조하기 위해 다양한 개수의 광 반응기를 갖는 화합물을 합성하였고 아크릴 공중합체에 도입하여 UV 경화형 아크릴 점착제를 제조하였다. 합성된 광반응성 화합물(f = 2 또는 3)의 구조는 NMR을 이용하여 확인하였다. 광반응성 화합물(f = 1~3)은 우레탄 반응을 통해 아크릴 점착제의 곁가지로 도입되었고, FT-IR 측정을 통해 UV 경화형 아크릴 점착제가 성공적으로 합성되었음을 확인하였다. UV 조사 전 후의 박리강도 변화는 실리콘 웨이퍼를 기재로 하여 평가되었으며, UV 조사 전 점착제의 높은 박리강도(~2000 gf/25 mm)가 UV조사 후 크게 감소(~5 gf/25 mm)하였다. 다 관능성 광 반응기가 도입된 점착제의 점착력 감소 효과가 가장 컸으며 FE-SEM을 통한 표면 잔류물 측정 결과, UV 조사 후의 표면 잔류물도 매우 낮은 수준(~0.2%)으로 관찰되었다.

• 한국기계가공학회지
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• 제19권6호
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• pp.96-101
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• 2020

In this paper, we present the results of our research to perform 3D laser scanning functions by adding a focusing lens to a conventional 2D laser scanner. For the optical design, the ray-tracing technique was used along with a total of four lenses as the variable incident focusing lens, the collimating lens, and the F-Theta lens. As design variables, the curvature of the incident focusing lens (Lens #1) was assumed to be us, l mm and sumed mm, and the incident angles were set at 0cidenus, l. In addition, the distance between the focusing lens and the collimating lens was set to vary from 5 mm to 15 mm. When the incident focal length was varied from 5 mm to 15 mm, the exit focal length was calculated to vary from 67.5 mm to 56.8 mm for the lens with R = 100 mm and from 108.5 mm to 99.0 mm for the lens with R = 150 mm. When the incident angle was 0°, the focal aberration was only slightly observable at 10㎛ in both the x- and y-direction. At 7.5° was the focal aberration of approximately 20~50㎛ was measured at 20㎛. To investigate the chromatic aberration of the designed optical device, the distortion of the focus was observed when the 550 nm beam was simulated on lens designed for a 980 nm wavelength.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.152-157
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• 2001

This paper is to model a 3D-shape product applying mathematically the data acquired from a 30 scanner and using an Automatic Design Program. The research studied in th reverse engineering up to now has been developed continuously and surprisingly. However, forming 3D-shape sol id models in CAE and CAM. based on the research, the study leaves much to be desired. Especially, analyses and studies reverse-designing automatically using measured data after manufacturing. Consequently, we are going to acquire geometric data using an 30 scanner in this study with which we will open a new field of reverse engineering by a program which can design a 3D-shape solid model in a CDA-based program automatically. Utilization of this program make it possible to minimize time in designing a product and establish a ADS(Automatic design system) program library to using all of the data from reverse engineering.

• 한국기계가공학회지
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• 제21권4호
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• pp.70-76
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• 2022

Calcium-phosphate-based bioceramics are promising biomaterials for scaffolds because they can assist in bone regeneration. In this study, a laser sintering deposition system was developed, and 3D hydroxyapatite (HA) scaffolds were fabricated. The main process conditions of the HA scaffolds were laser power, table velocity, and laser focal distance. As the laser power increased, the line width, line height, and layer thickness also increased. Further, the line width, line height, and layer thickness decreased as the table velocity increased. As the laser focal distance increased, the line width increased, but the line height and layer thickness decreased. The fabricated green scaffolds were sintered at 1050 ℃ and 1150 ℃. The sintered scaffolds had a uniform and continuous interconnected shape, with pore sizes ranging from 850 to 950 ㎛ having 53% porosity. The compressive strength of the scaffolds decreased from 0.72 MPa (1050 ℃) to 0.53 MPa (1150 ℃). The biocompatibility of the scaffolds was investigated by analyzing the adhesion of osteoblast-like MG-63 cells cultured on the surfaces of the scaffolds. The results indicate that the scaffold sintered at 1050 ℃ had good mechanical and biological properties compared to that at 1150 ℃.

• 한국염색가공학회지
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• 제30권1호
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• pp.38-50
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• 2018

This investigation reported the recent development of 3 dimensional fabrics such as spacer fabric, 3 dimensional multi-layered fabric and 3 dimensional braided fabric. First, we categorized 3 dimensional fabrics into 3 main products; 3 dimensional woven fabrics, 3 dimensional knitted fabrics and 3 dimensional braided fabrics with reviewing the possible main applications. We also reported the research and development trends of 3 dimensional fabrics by analyzing technical trends in industry and research institutes at domestic and overseas. United State, Germany and Japan lead the manufacturing technology for the mainly preform related products to apply in aerospace, automotive, protections, architecture and clothing applications. Lastly, we reviewed the main products of the leading company which manufactured using the 3 dimensional fabrics.