• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.96-102
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• 2019

Reverse engineering involves duplicating a physical part by measuring and analyzing its physical dimensions, features, and material properties. By combining reverse engineering with three-dimensional (3D) printing, engineers can simply fabricate and evaluate functional prototypes. This design methodology has been attracting increasing interest with the advent of the Fourth Industrial Revolution. In the present study, we apply reverse engineering and 3D printing technologies to evaluate a fabricated automotive inner ring prototype. Through 3D printing, inner rings of various densities were prepared. Their physical dimensions were measured with a 3D scanning system. Of our interest was the effect of inner ring density on the physical dimensions of the fabricated prototype. We compared the design dimensions and physical dimensions of the fabricated prototypes. The results revealed that even the 20% density of inner ring was effective for 3D printing in terms of satisfying the design requirements.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.25-30
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• 2019

In this paper, we have analyzed manufacturing problems of the scaffold with pores using FDM 3D printer and PLGA. We suggested the solutions using 3SC practical TRIZ. We selected the final solution used machine learning. We reduced number of experiments using most influential factor after analysis print factors. We printed the scaffold and measured pore size. We created the regression model using python tensorflow. The print condition data of measured pore size was used as training data. We predicted the pore size of printed condition using regression model. We printed the scaffold using the predicted the print condition data. We quantitatively compare the predicted scaffold pore size data and the measured scaffold pore size data. We got satisfactory result.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.247-248
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• 2022

3D printer-based self-healing capsules have been proposed to heal cracks by enabling various structural designs, repeatable fabrication, and strength analysis of the capsules. The Fusion Deposition Modeling (FDM) method was used to design, analyze, and produce new self-healing capsules that are widely used at low cost. However, PLA extruded from FDM has low interlayer adhesion energy, and thus strength varies depending on the angle of load applied to the laminated layer and the concrete structure, thereby degrading the performance of the self-healing capsule. Therefore, in this paper, the structure of the capsule manufactured by the FDM PLA method has isotropic strength was designed. In addition, the fracture strength in the x, y, and z directions of the load applied through the compression test was analyzed. As a result, it was confirmed that the newly proposed capsule design has an isotropic fracture strength of 1400% in all directions compared to the existing spherical thin-film capsule.

• Journal of the Korean Society of Radiology
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• v.11 no.5
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• pp.371-377
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• 2017

General phantom for practical X-ray photography Practical phantom is an indispensable textbook for radiology, but it is difficult for existing commercially available phantom to be equipped with various kinds of phantom because it is an expensive import. Using 3D printing technology, I would like to make the general phantom for practical X-ray photography less expensive and easier. We would like to use a skeleton model that was produced based on CT image data using a 3D printer of FDM (Fused Deposition Modeling) method as a phantom for general X-ray imaging. 3D slicer 4.7.0 program is used to convert CT DICOM image data into STL file, convert it to G-code conversion process, output it to 3D printer, and create skeleton model. The phantom of the completed phantom was photographed by X - ray and CT, and compared with actual medical images and phantoms on the market, there was a detailed difference between actual medical images and bone density, but it could be utilized as a practical phantom. 3D phonemes that can be used for general X-ray practice can be manufactured at low cost by utilizing 3D printers which are low cost and distributed and free 3D slicer program for research. According to the future diversification and research of 3D printing technology, it will be possible to apply to various fields such as health education and medical service.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.3
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• pp.1-8
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• 2017

Tool path generation is a part of process planning in 3D printing. This is done before actual printing by a computer rather than an AM machine. The mesh geometry of the 3D model is sliced layer-by-layer along the Z-axis and tool paths are generated from the sliced layers. Each 2-dimensional layer can have two types of printing paths: (i) shell and (ii) infill. Shell paths are made of offset loops. During shell generation, twists can be produced in offset loops which will cause twisted tool paths. As a twisted tool path cannot be printed, it is necessary to remove these twists during process planning. In this research, An algorithm is presented to remove twists from the offset loops. To do so the path segments are traversed to identify twisted points. Outer offset loops are represented in the counter-clockwise segment order and clockwise rotation for the inner offset loop to decide which twisted loop should be removed. After testing practical 3D models, the proposed algorithm is verified to use in tool path generation for 3D printing.

• Progress in Medical Physics
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• v.28 no.3
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• pp.106-110
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• 2017

The variable density phantom fabricated with varying the infill values of 3D printer to provide more accurate dose verification of radiation treatments. A total of 20 samples of rectangular shape were fabricated by using the $Finebot^{TM}$ (AnyWorks; Korea) Z420 model ($width{\times}length{\times}height=50mm{\times}50mm{\times}10mm$) varying the infill value from 5% to 100%. The samples were scanned with 1-mm thickness using a Philips Big Bore Brilliance CT Scanner (Philips Medical, Eindhoven, Netherlands). The average Hounsfield Unit (HU) measured by the region of interest (ROI) on the transversal CT images. The average HU and the infill values of the 3D printer measured through the 2D area profile measurement method exhibited a strong linear relationship (adjusted R-square=0.99563) in which the average HU changed from -926.8 to 36.7, while the infill values varied from 5% to 100%. This study showed the feasibility fabricating variable density phantoms using the 3D printer with FDM (Fused Deposition Modeling)-type and PLA (Poly Lactic Acid) materials.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.123-134
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• 2020

With the recent development of 3D printers, there is a growing need to make them similar to real products. As a result, FDM full-color 3D printers have been developed and actively distributed, but GUI design has fallen short of that, causing confusion among users. Accordingly, this study conducted a literature survey, and through a case study, the current status of FDM full-color 3D printers was identified and the components of GUI design were analyzed based on prior research. The draft checklist was drawn up according to the components of the derived GUI design, and 24 items were deleted through the three Delphi surveys and the validity of the remaining 26 items was verified. As a result, the layout should consist of intuitive screen configuration and menus with high frequency of use, and the text should be intuitive and clearly communicated. In addition, the icon should be placed in a visible position and used in real life to image it. Finally, we could see that the color should be used to give feedback to the user using the highlight color and not overlap the output.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.46-50
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• 2019

In this paper, We used the regression model of machine learning for improve the print quantity problem when which print scaffold with 400 ㎛ pore using FDM 3d printer. We have difficult to experiment with changing all factors in the field. So we reduced print quantity by selected two factors that most impact the pore size. We printed and measured scaffold 5 times under same conditions. We created regression model using scaffold pore size and print conditions. We predicted pore size of untested print condition using the regression model. After print scaffold with 400 ㎛ pore, we printed scaffold 5 times under same conditions. We compare the predicted scaffold pore size and the measured scaffold pore size. We confirmed that error is less than 1 % and we verified the results quantitatively.

• Fashion & Textile Research Journal
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• v.21 no.3
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• pp.267-276
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• 2019

This study develops 3D-printed-garment collections for a fashion show presentation. A design concept using traditional patterns that consisted of garments regarding the limitation of the printing technology was investigated in order to develop the collection. The structures of the connecting joints of the textile parts which could be easily and sturdily interconnected were invented. Wearability as garments that could be naturally worn on the human body were sought. As a result, four 3D-printed-garments were developed. The 1st garment composed of objects based on a 'Yeon-Dang-Cho'-pattern was constructed as a geometric robe style using a FDM 3D printer and transparent TPU filaments. The 2nd and 3rd 3D-printed-garments composed of an object based on a 'Boe-Sang-Hwa'-pattern was constructed as a distorted one-piece exaggerating the silhouettes of shoulders and waist parts as well as a straight asymmetric tunic style that used the same printer and material as the 1st garment. The last garment composed of an object based on a 'Boe-Sang-Hwa'-pattern printed using a SLA 3D printer and flexible-liquid-resin was constructed attaching the objects on the fabric material by the hot-press machine. The four developed garments were presented in the opening fashion show of 'the 6th International 3D-printing Korea Expo'. This study provides a basic case for related studies to adapt 3D-printing technology in textile pattern development of garment construction.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.41-47
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• 2021

Purpose: This study aimed to compare the accuracy of 3-dimensional(3D) printed models derived from multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) systems with different fields of view (FOVs). Materials and Methods: Five human dry mandibles were used to assess the accuracy of reconstructions of anatomical landmarks, bone defects, and intra-socket dimensions by 3D printers. The measurements were made on dry mandibles using a digital caliper (gold standard). The mandibles then underwent MDCT imaging. In addition, CBCT images were obtained using Cranex 3D and NewTom 3G scanners with 2 different FOVs. The images were transferred to two 3D printers, and the digital light processing (DLP) and fused deposition modeling (FDM) techniques were used to fabricate the 3D models, respectively. The same measurements were also made on the fabricated prototypes. The values measured on the 3D models were compared with the actual values, and the differences were analyzed using the paired t-test. Results: The landmarks measured on prototypes fabricated using the FDM and DLP techniques based on all 4 imaging systems showed differences from the gold standard. No significant differences were noted between the FDM and DLP techniques. Conclusion: The 3D printers were reliable systems for maxillofacial reconstruction. In this study, scanners with smaller voxels had the highest precision, and the DLP printer showed higher accuracy in reconstructing the maxillofacial landmarks. It seemed that 3D reconstructions of the anterior region were overestimated, while the reconstructions of intra-socket dimensions and implant holes were slightly underestimated.