• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.547-552
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• 2003

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR (material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over 300m. so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL(cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants wire applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to speaker mold machining. The finishing time was reduced to 12.6%. tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were removed.

• Journal of Fashion Business
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• v.10 no.6
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• pp.16-27
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• 2006

The purpose of this study was to examine the effects of chemical finishes on performance characteristics of microfiber blend fabrics. A 60% polyester microfiber /40% cotton blend woven fabric was finished by ten chemicals: three silicone softeners, one fluorochemical, and their mixtures. Performance characteristics examined were fabric hand attributes. Fabric hand was evaluated by instrumental measures using Kawabata KES-F system instruments. Silicone-only finishes did not change the bending properties significantly from those of the control fabric. The fluorochemical-only finish made the fabric stiffer and crisper. When the two chemicals were mixed they tended to offset this adversary effect. Most of the chemical finishes made the surface finer and smoother. Fluorochemical-only finish improved fabric strength. Likewise, dimethylpolysiloxane silicone improved fabric strength. Amino-functional hydrophilic and diamino-functional silicone softeners, on the other hand, reduced fabric strength. However, when mixed with the fluorochemical, the adversary effect was diminished.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.8
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• pp.834-839
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• 2012

Recently, mechanical components with miniaturized size, complex shape and fine surface are on demand from industries such as mobile electronics, medical devices and defense. The size of them is smaller than several millimeters, the shape has micro-holes, curve, or multi-step and the surface is mirror-like. This features are not able to be machined with the conventional machining, therefore electro-discharge machining (EDM), cutting, and laser machining have been applied. If the technologies are assisted by vibration, high aspect ratio and good surface are to be achieved. In this paper, prior and current researches of vibration-assisted machining are reviewed. Machining mechanisms with vibration-assisting are explained, their effects are shown, and vibrating apparatuses are discussed. Especially, comparison between with and without vibration assisting is presented. This review shows the vibration-assisted machining is effectively fabricate the components with small and complicated shape and fine surface finish.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.217-223
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• 2005

This study is on the evaluation of three kinds of surface protectors for protecting reinforced concrete against corrosion of reinforcing steel by chloride attack and carbonation. In this study, the test has been carried out on the performance of specimens applied with surface protectors for anti-corrosion and anti-carbonation. The result showed that specimens applied with the three kinds of surface protectors, were excellent in resistance to the corrosion of reinforcing steel and carbonation. Especially the specimen applied with finish coating in conjunction with hydrophobic primer showed great reduction in the corrosion of reinforcing steel and carbonation.

• Journal of Fashion Business
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• v.11 no.4
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• pp.101-110
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• 2007

Since cotton fabrics with ripple finish treatment form wavy furrows on the surface or bumpy patterns, air circulation during wearing is good and the fabric is cool to the touch. The finishing principle is based on the mercerization, which utilizes the fact that cotton fibers contract in a concentrated NaOH solution. In this study, as fabric specimens, cotton fabrics with yarn counts of 40's, 60's and 80's were used. Concentrations of the NaOH solutions were 15%, 25%, and 35%. After dyeing fabrics using Rubia akane nakai, color and other properties were measured. As the concentration of the NaOH solution increased, the fabric became thicker and denser, and the number of occurrence of the prominence and depression per unit length became larger. The color of the region contracted by ripple finish became darker after dyeing, while the color of the untreated region became lighter, which enhanced the cubic effect of the ripple finish. As the count of the cotton yarn increased, the dyeability became better. As the concentration of the NaOH solution increased, the air permeability became lower.

• Textile Coloration and Finishing
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• v.17 no.6 s.85
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• pp.27-35
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• 2005

Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

• Korean Journal of Heritage: History & Science
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• v.50 no.4
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• pp.148-165
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• 2017

Mural paintings drawn inside ancient tombs are very sensitive to changes in the environment such as temperature and humidity, especially the finish layer of the tomb murals differ in preservability depending on the material properties and humidity conditions. In this study, I examined the mural painting of Songsan-ri Tomb No.6, where the finish layer was made of earth, and identified the physical changes that can occur due to drying, depending on the material properties of the finish layer. I found out through particle size analysis that the finish layer of the mural painting in Songsan-ri Tomb No.6 is about 85.0wt% below silt, about 14.0wt% clay therein, mostly composed of silt and below clay. I also found out through physical property evaluation that surface change rate of samples showed the largest change at 15.5% in reproduced finish layer sample made up of bentonite, followed by 7.8% of reproduced finish layer sample made up of celadon soil, 6.3% of reproduced finish layer sample made up of loess, 6.2% of reproduced finish layer sample composed of white clay and the same order of change in appearance was confirmed in each sample consisted of soil. In addition, it showed the same trend of surface change rate, and the bentonite condition showed the largest change, in the measurement of shrinkage rate and expansion rate. The experiment shows that the finish layer composed of soil is affected by cohesion among particles according to the content of fine parts and the relationship between the agglomeration due to the content of the differentiated part and the stress due to the expansibility depending on the kind of the clay mineral etc. Therefore, it can be concluded that the physical damage occurred in the mural painting finish layer of the Songsan-ri Tomb No.6 is related to the factors such as the material characteristics of the soil and the highly humid environmental change inside the tomb.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• v.5 no.5
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• pp.583-591
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• 2018

Tool-chip adhesion impacts on cutting performance significantly, especially in finish cutting process. To promote cutting tools' anti-adhesion property, the concave micro-grooves texture (MGT) and convex volcano-like texture (VLT) were fabricated separately on lathe tools' rake faces by laser surface texturing (LST). Various orientations of MGT and different area densities (9% and 48%) and regions (partial and full) of VLT were considered in textured patterns designing. The following orthogonal cutting experiments, machining of aluminum alloy 5038, analyzed tools' performances including cutting force, cutting stability, chip shape, rake face adhesion and abrasion. It indicated that under dry finish cutting conditions, MGT contributed to cutting stability and low cutting forces, meanwhile friction and normal force reduced by around 15% and 10%, respectively with a weak correlation to the grooves' orientation. High density VLT tools, on the other hand, presented an obvious anti-adhesion property. A $5{\mu}m$ reduction of crater wear's depth can be observed on textured rake faces after long length cutting and textured rake faces presented half size of BUE regions comparing to the flat tool, however, once the texture morphologies were filled or worn, the anti-adhesion effect could be invalid. The bearing ratio curve was employed to analysis tool-chip contact and durability of textured surfaces contributing to a better understanding of anti-adhesion and enhanced durability of the textured tools.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.313-314
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• 2002

SiCp-reinforced metal matrix composites (MMCs) containing 8 wt % and 16 wt % of $SiC_p-reinforced$ with 30 and $45\;{\mu}m$ in sizes were prepared by a melt stirring-squeeze casting technique. Microstructural observation showed that particle distributions were reasonably well. Turning experiments were carried out on the composites using uncoated and triple-layer coated carbide tools at various cutting speeds under a constant feed rate and depth of cut. Coated tools indicated better performance than uncoated tools for all the materials while the poor surface finish was obtained for coated tools.

• Corrosion Science and Technology
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• v.2 no.5
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• pp.219-224
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• 2003

Crevice corrosion of stainless steels in natural seawater was investigated for several post weld treatments; as-annealed, as-welded, pickled, and ground. The results confirmed the effect of the biofilm on the cathodic reaction leading to an ennoblement of the rest potential. The degree of ennoblement of corrosion potential depends on the surface finish. As-annealed and pickled samples show stable corrosion potential approaching to 200 ~ 300 mV (SCE) while as-welded and ground samples show the fluctuating corrosion potential. This points to a situation where there are conflicting effects determining the trend in free corrosion potential. Crevice corrosion initiation will tend to pull the free corrosion potential in the active direction, whereas the presence of biofilm will tend to ennoble corrosion potential. There was no visible attack on UNS S31803, S32550, and 2205W. Therefore, those stainless steel grades appeared to be resistant to crevice corrosion in natural seawater on condition of weld metal.