• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.139-152
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• 2023

Despite efforts to apply 3D print (3DP) technology in the field of fashion and endless discussions about the possibility of future development, in reality, it is difficult to utilize 3DP technology in fashion for reasons related to material, technology, and cost constraints. The purpose of this study was to supplement the limitations of 3DP technology in order to promote its utilization in fashion and simultaneously find a solution to achieve aesthetic satisfaction in the design method. Specifically, through the development of fashion products with a 3DP polymer-fabric structure to which the parametric design methodology has been applied, this study explored the possibility of practical application and proposes a new 3DP fashion design method. The 3DP polymer-fabric developed as a result of the research was stably adhered to the fabric. Additionally, the study confirmed the possibility of making 3DP clothes that are amenable to the wearer's activities, as it was verified that cutting and sewing tailored to the human body's curvature and structure can be performed. The design process using the 3DP polymer-fabric presented in this study is meaningful in that it suggests a solution to complement the limitations of modern technology in connection with designers' creativity. Moreover, the design process presented in this study is expected to contribute to the commercialization and generalization of 3DP by providing practical help to allow fashion experts to utilize 3DP technology.

• Design & Manufacturing
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• v.11 no.1
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• pp.14-18
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• 2017

Recently, the injection-molded products are lighter, and thinner than ever. In this work, Injection molding simulation was conducted to analysis the filling pattern imbalance in high speed injection molding process for thin-wall injection component, 8 inches LGP. Numerical analysis shows that shear heated polymer near the side wall causes filling imbalance between center and side of cavity. Short shot experiments were conducted and compared with simulation results. Filling imbalance ratio showed a tendency to increase for wider fan gate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.2
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• pp.130-138
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• 2006

We have investigated pattern scaling down of silicon stamps through the oxidation technique, During oxidizing the silicon stamps, silicon dioxide that has 300 nm and 500 nm thickness was grown, and critical deformations were not observed in the patterns. There was positive effect to reduce size of patterns because vertical and horizontal patterns have different orientation. We achieved pattern reduction rate of $26\%$. In addition, the formation of polymer patterns had been investigated with varied temperature and pressure conditions to improve the filling characteristics of polymers during nanoimprint lithography when pattern sizes were few micrometers. In these varied conditions, polymers had been affected by free space compensation and elastic stress relaxation for filling the cavities. Based on the results, defect control which is an important issue in the nanoimprint lithography were facilitated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1174-1177
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• 2003

In this study, to achieve the optimal conditions for mechanical hyper-fine pattern fabrication process, deformation behavior of the materials during indentation was studied with numerical method by ABAQUS S/W. Polymer (PMMA) and brittle materials (Si, Pyrex glass) were used as specimens, and forming conditions to reduce the elastic recover and pile-up was proposed. The indenter was modeled a 3D rigid surface. Minimum mesh sizes of specimens are 1-10nm. Comparison between the experimental data and numerical result demonstrated that the finite element approach is capable of reproducing the loading-unloading behavior of a nanoindentation test. The result of the investigation will be applied to the fabrication of the hyper-fine pattern.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.4 s.181
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• pp.162-167
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• 2006

Hot embossing lithography(HEL) has the production advantage of comparatively few process step, simple operation, a relatively low cost for embossing tools(Si), and high replication accuracy for small features. In this paper, we considered the nano-molding characteristic according to molding parameters(temperature, pressure, times, etc) and induced a optimal molding condition using HEL. High precision nano-patter master with various shapes were designed and manufactured using the DRIE(Deep Reactive ion Etching), LPCVD(Low Pressure Chemical Vapor Deposition) and thermal oxidation process, and we investigated the molding characteristic of DVD and Blu-ray nickel stamp. We induced flow behaviors of polymer, rheology by shapes and sizes of the pattern through various molding experiments. Finally, with achieving nano-structure molding with high aspect ratio, we will secure a basic technology about the molding of large-area nano-pattern media.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.505-506
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• 2006

This study is focused on the manufacturing technique of powder injection molding of watch case made from zirconia powder. A series of computer simulation processes were applied to the prediction of the flow pattern in the inside of the mould and defects as weld-line. The material properties of melted feedstock, including the PVT graph and thermal viscosity flowage properties were measured to obtain the input data to be used in a computer simulation. Also, a molding experiment was conducted and the results of the experiment showed a good agreement with the simulation results for flow pattern and weld line location. On the other hand, gravity and inertia effects have an influence on the velocity of the melt front because of the high density of ceramic powder particles during powder injection molding in comparison with polymer's injection molding process. In the experiment, the position of the melt front was compared with the upper gate and lower gate positions. The gravity and inertia effect could be confirmed in the experimental results.

• Macromolecular Research
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• v.15 no.5
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• pp.396-402
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• 2007

The dielectric properties and various pattern-forming states of dual-frequency material in a nematic phase, as well as its mixture containing low concentrations of reactive monomers, are reported. The dielectric relaxation behaviors of nematic MLC 2048 are presented and compared to its mixture containing both mesogenic and nonmesogenic reactive monomers. The sign-inversion frequency of the dielectric anisotropy was significantly shifted on the addition of small amounts of the reactive monomers. However, all three mixtures used in this study essentially exhibited the same field-induced instabilities at different frequencies and voltage domains of the applied electric field. A broad band of modulated states were found to exist above a critical voltage and within a voltage dependent frequency band in the vicinity of the sign-inversion frequency, $f_I$, of the dielectric anisotropy. As the $f_I$ of the mixtures shifted, so did the bands of the modulated state of the different mixtures and the temperatures, which were well matched with the measured $f_I$ value.

• Tribology and Lubricants
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• v.35 no.6
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• pp.337-342
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• 2019

This paper presents an experimental investigation of friction and wear characteristic with respect to patterns occurring on the surface of 3D printed polymer products by fused deposition modeling method. The purpose of this study was to investigate the effect of the patterns and sliding directions on the tribological properties of 3D printed polymer surface. A cubic specimen was printed using polylactic acid filament as the printing material. Friction tests were conducted for different directions with respect to the patterns that were generated on the top and the side surfaces of the specimen, by using a ball-on-reciprocating type tribotester. SUJ2 bearing ball of which the diameter was 11 times greater than the width of the largest pattern was used as the counter surface to assess the frictional behavior. Friction tests were conducted on the top and the side surfaces with respect to the patterns in 3 (0°, 45°, 90°) different directions respectively. Coefficient of friction increased as cycles increased in all cases. The results of the tests showed that the lowest coefficient of friction was measured with the 45° sliding direction on the side surface. The wear rate was the lowest at 45° sliding direction on the side surface, while it was the highest at 0° sliding direction on the top surface. Coefficient of friction of about 0.45 was determined to be the converging value on the top compared to the side surface.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.590-595
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• 2004

The shape and size variations of the nanopatterns produced on a positive photoresist using a near-field scanning optical microscope(NSOM) are investigated with respect to the process variables. A cantilever type nanoprobe having a 100nm aperture at the apex of the pyramidal tip is used with the NSOM and a He-Cd laser at a wavelength of 442nm as the illumination source. Patterning characteristics are examined for different laser beam power at the entrance side of the aperture( $P_{in}$ ), scan speed of the piezo stage(V), repeated scanning over the same pattern, and operation modes of the NSOM(DC and AC modes). The pattern size remained almost the same for equal linear energy density. Pattern size decreased for lower laser beam power and greater scan speed, leading to a minimum pattern width of around 50nm at $P_{in}$ =1.2$\mu$W and V=12$\mu$m/. Direct writing of an arbitrary pattern with a line width of about 150nm was demonstrated to verify the feasibility of this technique for nanomask fabrication. Application on high-density data storage using azopolymer is discussed at the end.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.3
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• pp.344-349
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• 2017

In this study, we developed a process technology to fabricate RFID tag antennas using a one-sheet inlay micro-pattern forming process by press-molding RFID tag antennas on insulation sheet layers, such as polymer films, using ultrasonic longitudinal vibration. In addition, a fine pattern applicable for RFID tag antennas was manufactured using a $25{\mu}m$ thick thin-plate square wire; this is in contrast to the method that uses a conventional round wire. The developed ultrasonic indentation process can be used to fabricate fine pattern of the RFID antenna using one piece of equipment. The simplified manufacturing process technology has a shorter manufacturing time and is more economical. The developed RFID tag antenna forming technique involves pressing the $25{\mu}m$ square wire directly on the thin sheet insulation sheet of maximum thickness $200{\mu}m$, using a 60 kHz ultrasonic tool horn.