• Journal of the Korean Society of Radiology
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• v.12 no.7
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• pp.909-917
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• 2018

3D printing technology is expected to be an innovative technology of the manufacturing industry during the 4th industrial revolution, and it is being used in various fields including biotechnology and medical field. In this study, we verified the printing materials through Monte Carlo simulation to evaluate the radiation shielding ability of the raw material using this 3D printing technology. In this paper, the printing materials were selected from the raw materials available in a general-purpose FDM-based 3D printer. Simulation of the ICRU phantom and the shielding system was carried out to evaluate the shielding effect by evaluating the particle fluence according to the type and energy of radiation. As a result, the shielding effect tended to decrease gradually with increasing energy in the case of photon beam, and the shielding effect of TPU, PLA, PVA, Nylon and ABS gradually decreased in order of materials. In the case of the neutron beam, the neutron intensity increases at a low thickness of 5 ~ 10 mm. However, the effective shielding effect is shown above a certain thickness. The shielding effect of printing material is gradually increased in the order of Nylon, PVA, ABS, PLA and TPU Respectively.

• 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 Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.3
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• pp.468-486
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• 2017

In this study, three kinds of wearable fashion prototypes were developed using 3D printers with the goal of developing a practical production method for daily clothes. Prototypes were modeled using Rhinoceros software and developed using FDM 3D printers and TPU filaments. The results of this study are as follows. First, it confirmed the possibility of FDM-type entry-level 3D printers as a tool to develop wearable fashion products. Second, TPU filaments that are soft and ductile are highly likely to be used as a clothing material. Third, patterns designed through the 3D modeling process can be sampled directly to a 3D printer and easily corrected and supplemented. Fourth, it was confirmed that TPU prints of about 1.00mm thickness can be sewn with fabric using sewing machines through the development of 'Prototype 1' and 'Prototype 2'; in addition, hand stitching is also possible. Fifth, as in the case of 'Prototype 3', it is possible to fabricate a garment fit enough to the body if the clothing configuration is designed to connect the basic module using TPU filaments. In the future, the development of wearable fashion prototypes using various materials and 3D printing technology will help diversify everyday clothes.

• 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 Clothing and Textiles
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• v.45 no.1
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• pp.155-167
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• 2021

The latest innovation in the field of fashion comes in the form of 3D-printed clothing. This study explores the composition and characteristics of the shapes in the architecture of Zaha Hadid, a representative architectural designer who expresses space in three dimensions. Hadid applies his aesthetic to fashion design using these distinctive geometric shapes to create design motifs as well as develop new clothing material with 3D printing technology. The research was conducted as follows. First, the lines and arrangement of the geometric shapes in Zaha Hadid's architecture were analyzed so that his design principles could be used as a theoretical basis for this study. The study also reviewed geometric fashion designs using 3D printing technology over the last ten years. Second, we developed triangular modules with rods and tongs that could be fashioned into clothing using fused deposition modeling (FDM) 3D printers. Lastly, the 3D printing fashion design was developed to explore new silhouettes, textures, and a novel way of producing clothing. This study hopes to serve as a stepping-stone for further research on innovations that combine fashion with technology.

• 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.

• Journal of the Korea Fashion and Costume Design Association
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• v.17 no.2
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• pp.125-143
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• 2015

This study has investigated the status of utilizing 3D printing in fashion field in order to keep up with the trend for 3D printing technology to be realized in all industries so that the materials and the modeling modes may be figured out. The following is the findings. The materials used most in 3D printing in fashion field are PA, PLA, TPU, multi-material, ABS and metal. PA, TPU and Multi-material have so much excellent flexibility and strength that they are widely used for garment, shoes and such fashion items as bags. But PLA, ABS and metal are scarcely used for garment because PLA is easily biodegradable in the air, ABS generates harmful gas in the process of manufacture and metal is not flexible, while all of these three are partly used for shoes and accessories. The modeling modes mainly applied for 3D printing in fashion field are SLS, SLA, FDM and Polyjet. SLS, which is of a powder-spraying method, is used for making 3D textile seen just like knitting. Polyjet method, which has higher accuracy and excellent flexibility, can be used for expressing diverse colors, and accordingly it is used a lot for high-quality garment, while SLA and FDM method are found to be mostly used for manufacturing shoes and accessories rather than for making garment because they are easily shrunk to result in deformation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.191-192
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• 2006

In these days, various kinds of rapid prototyping processes are available, such as stereo-lithography apparatus(SLA), fused deposition modeling(FDM), selective laser sintering(SLS), 3 dimensional printing(3DP), and laminated object manufacturing(LOM). For detailed informations about mechanical properties of those parts, benchmark tests are carried out. SLS and EOS part has an advantage in compressive strength, SLA has in hardness, FDM part has in impact strength, and LOM part has an advantage in tensile strength and heat resistance. The change of building direction in layered manufacturing processes of FDM and LOM severely weakens the tensile and impact strength.

• Journal of the Semiconductor & Display Technology
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• v.17 no.4
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• pp.70-75
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• 2018

In this paper, we have studied the deformation problem of the scaffold caused by the FDM type 3D printer. The DOE (Design of experiment) and 3SC was used to solve the deformation problem of the scaffold generated from the adhesion surface between the scaffold and the bed. The methodology was used to derive the solution and the experiment was conducted on the derived solution. As a result of evaluating the experimental results obtained for the solution, it was found that the deformation of the scaffold was much improved. By using the DOE, We were possible to derive the output condition of scaffold.