• Transactions of Materials Processing
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• v.17 no.5
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• pp.322-327
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• 2008

LGP is a key component of LCD back light unit because it determines brightness and sharpness of the display image. Usually, it has optical patterns fabricated on the bottom surface. These optical patterns convert point or line sources placed in the side of LGP to plane source at the top surface by changing the propagating direction of the incident light. In the present paper the LiGA-reflow method was applied to fabricate the LGP mold. Furthermore, the optical simulation considering the replication ratio of pattern height was applied to the pattern design. The optical simulation through systematic correction scheme was adopted to find the optimum distribution of pattern density. Finally, the stamper fabricated by this method was installed in the mold and LGP was produced by injection molding. As a result of luminance measurement for the final product, the average luminance and luminance uniformity was measured 3,180 nit and 84%, respectively. Consequently, the mold fabrication method using the LiGA-reflow and optical simulation(CAE) can save the expense and time compared with the existing fabrication methods(laser ablation and chemical etching).

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.269-272
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• 2008

LGP is a key component of LCD back light unit because it determines the brightness and sharpness of display image. Usually, it has optical patterns fabricated on the bottom surface. In the present paper the LiGA-reflow method was applied to fabricate the LGP mold. Furthermore, the optical simulation considering the replication ratio of pattern height was applied to the pattern design. The optical simulation through systematic correction scheme helped find the optimum distribution of pattern density. Finally, the stamper fabricated by this method was installed in the mold and LGP was produced by injection molding. As a result of luminance measurement for the final product, the average luminance and luminance uniformity was measured 3,180 nit and 84%, respectively. Consequently, the mold fabrication method using the LiGA-reflow and optical simulation(CAE) can save the expense and time compared with the existing fabrication methods(laser ablation and chemical etching).

• Journal of Korean Society for Quality Management
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• v.25 no.1
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• pp.135-141
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• 1997

The Copper-Clad Laminate (CCL) is a main electronic component of specialtype printed circuit boards (PCBs) such as Silver Through Hole PCB. This CCL should have high reliability under the aging test, and usually the test is done at a higher temperature (110-$150^{\circ}C$) than the normal. Then, this test condition of high temperature may cause such quality problems as hole eccentricity and reduction of distance between part holes. After measuring the CCL shrinkage affected by temperature, the correction factor of a press mold was a, pp.ied to solve these problems. The results showed that the tolerance of hole pitch(${\pm}$$100{\mu}m$) was satisfactory and the internal and external failure costs were reduced by 55%.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.811-816
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• 2011

We develop a plastic object lens for blu-ray disc playing pick-up module as morethan 0.85 numerical aperture in this research. We design plastic object lens for blu-ray disc playing pick-up module's each factor's in balanced and made our designed lens by injection molding. Furthermore, by correction designing in mold-core, we optimization our lens efficiency as world grade; wave front aberration $0.028{\lambda}$. RMS, light axis differential 0.3967arcmin. We can manufacture localized blu-ray disc's pick-up lens's component and by this fact we obtain international competitiveness. The result of this research will be very helpful to develop a single objective lens for 3 different wavelength of laser diodes in playing and recording pick-up module.

• Journal of Mechanical Science and Technology
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• v.14 no.1
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• pp.65-71
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• 2000

Mold cavities of gears should be made larger than the product specification since plastics shrink when changing from a molten to a solid state. For injection molded spur gears, two design methods for the compensation of shrinkage are widely used. One is the module correction method and the other is the pressure angle correction method. Both methods are based on the assumption that shrinkage occurs toward the center of a molded gear. This paper deals with the shrinkage rate and proposes a method of designing gear cavity derived from the measured shrinkage rates which govern the outside diameter, the tooth depth and the tooth thickness of a molded gear. The proposed method imposes no restriction on the shrinkage direction and provides a cavity with all of the fundamental gear design parameters.

• Transactions of the KSME C: Technology and Education
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• v.1 no.1
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• pp.13-19
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• 2013

Ftheta Lens, whose image height is proportional to its field view angle, is one of the most important parts in Laser Scanning Unit(LSU). In this paper $f{\theta}$ lens design, mold production and modification method of lens design and mold are introduced. Lens design was carried out with Zemax and Special Toric surfaces were applied for lens surfaces to minimize distortion both in main and sub scanning directions. And a high precision machine with 1nm resolution was used to fabricate lens mold cores. After injection the lens was evaluated and the difference from design was examined. This difference was compensated by modifying lens design and new lens mold cores were made according to modified lens design to obtain the quality of original design.

• Journal of Chest Surgery
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• v.45 no.6
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• pp.418-420
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• 2012

Pectus excavatum is rare, but it is the most common type of sternal congenital disorder. There are many surgical methods to correct pectus excavatum such as the Ravitch method, Wada method, Silastic mold method, and the Nuss operation. We report a case of minimal invasive surgery for pectus excavatum using a polyvinyl alcohol sponge.

• Design & Manufacturing
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• v.12 no.1
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• pp.52-57
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• 2018

With the recent strengthening of environmental regulations and the need for cost reduction, excavators, a type of construction equipment, are being miniaturized while components are being developed in consideration of stability. In the case of excavator press parts, mainly high-strength steel sheets are being used to enhance stability and reduce weight. However, in the case of high-strength materials, there is a need to research product forming methods to reduce Springback in defects arising in parts assembly due to Springback that result from the internal residual stress that occurs in press forming being released after product forming. Accordingly, regarding the tank cover, an excavator press-forming part, this study selected a method to reduce distortion through analysis of the Springback occurrence rate and Springback causes through a forming analysis. A forming analysis was conducted for the Springback of the tank cover. Deformations of 13.714 mm in the upper part and 6.244 mm in the inner part of the product occurred, while wrinkles occurred on the sides of the product due to uneven thickness. A forming analysis was conducted for the major shapes of the product to investigate the causes of Springback. Distortion deformation due to the bead in the center of the product was confirmed to be a large factor. A Springback reduction method of correcting uneven thickness in the product sides, a Springback reduction method of removing the bead, and a correction method of restriking after the final forming were used in a forming analysis to determine the degree of Springback reduction. For the forming method to correct uneven thickness in the sides, deformation was reduced by 12% in the upper side compared to the existing model, but deformation in the inner side increased by 1%. For the restriking forming method, deformation decreased by 25% in the upper side and 13% in the inner side. For the bead removal method, deformation decreased by 28% in the upper side and 13% in the inner side, the largest Springback correction results. This indicates that the bead has a large affect on Springback.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.4
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• pp.673-685
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• 2010

This study evaluates the fitness of brassieres through size measurement, comparative pattern analysis, cross section map analysis, 3-D shape analysis number, and fitness evaluation with a focus on domestic and overseas brands. Experimental brassieres were selected as mold brassieres of 3/4 cup in 75A size that is considered a popular design. Brands of selected brassiere were 2 domestic brands (A, B), 1 licensed brand (C), and 2 overseas brands (D, E). Subjects were 8 women in their early 20's. Data were analyzed by descriptive statistics, analysis of variance, reliability analysis, and factor analysis. The results were as follows; the size and pattern of brassieres showed a difference by each brand even though brassieres are the same design. In the wearing effect of brassieres, overseas brand brassieres played a major role in the breast-up effect, but they were not appropriate for the somatotype of Korean women. Domestic brand brassieres showed the volume-up effect, that was confirmed by the increasing bust circumference, bust depth when subjects wore it. In addition, the licensed brand brassieres showed the correction effect of body shape. Therefore, when purchasing a brassiere, the most important condition is to consider the individual characteristics of the somatotype. The results of factor analysis through a functional evaluation show that wearing satisfaction, size satisfaction, and the position of the bust point were important factors for fitness satisfaction and purchase.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.590-595
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• 2014

We have investigated anamorphic prism lenses with distortions of 0.3-0.5%. We designed the plastic triangular lens and confirmed the minimum resolution using MTF graphs. Also we confirmed that the SVGA optical system can realize a resolution of $864{\times}648$ 56 megapixels. A distortion of about 0.5% aberration appears in the maximum field, and a finite beam aberration of about $15{\mu}m$ is confirmed. We made a mold based on the design data and completed the prism lens through exodus molding. We confirmed the shape error (< $30{\mu}m$) and surface roughness (> 40 nm) of the three sides. We made the video-information-display prototype glasses using prism lens by measuring the performance, we determined the distortion aberration (0.3%) and SVGA resolution. Our approach will enable fabrication of a portable large-screen display device for glasses and sunglasses for the domestic market and, after 2015, for the world market.