• Polymer(Korea)
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• v.38 no.2
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• pp.193-198
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• 2014

Lens and DVD require high quality of optical property. Conventional injection molded products contain high residual stress and this invokes birefringence since high cavity pressure and high temperature variation are involved in a molding process. Thus these products are often molded by injection compression molding in order to minimize the residual stress through reducing cavity pressure and uniform cavity pressure. In this study, molding parameters affecting molding quality such as property uniformity in injection compression molding were investigated through experiment. Molding quality deviations among the cavities in multi-cavity mold were also studied. Transparent resins, PC and PS were used in this study. Compression gap, compression speed, compression force, and compression delay time for processing variables in injection compression molding were applied in experiment. Compression force, compression delay time, and compression gap significantly affected the optical property of product. The degree of influence of process variable on the product quality was different in different resins. This implies that the optimal operational conditions in injection compression molding existed for each resin according to flow property.

• Korean Journal of Computational Design and Engineering
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• v.9 no.2
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• pp.112-121
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• 2004

As customers demands are rapidly changing, a product life cycle is getting shorter and a product model is forced to be changed frequently. An ejecting design system becomes more important for high productivity to eject a product in high temperature without any damage. For example, an ejector pin that is a key component of the system can cause high local stresses and strains in the molding at the time of ejection. The number, the size, and the location of pins are important to make a smooth ejection. Therefore we propose an analytical approach with the aid of designer’s experience to calculate a total release force and pressure distribution so that the number, the size, and the location of pins can be easily determined. As a part of the result, the design system is built by Intent! with AutoCAD 2000 and a video player deck example is presented to verify the approach.

• Korean Journal of Computational Design and Engineering
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• v.11 no.1
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• pp.41-48
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• 2006

This paper describes hexahedral mesh generation for various shell structures, such as automobile bodies, plastic injection mold components and sheet metal parts by using chordal surfaces. After generaling one-layered tetrahedral mesh by an advancing front algorithm, the chordal surfaces are constructed by cutting of tetrahedral elements. Since the choral surfaces are composed of tri/quad elements with poor quality, they are transformed into quadrilateral elements with good quality. Hexahedral elements are then generated by offsetting these quadrilateral elements. The boundary nodes of hexahedral elements are generated on the outer surfaces of the original shell structures. Sample models including nonuniform thickness have been tested to validate the proposed algorithm.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.380-382
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• 2006

신재생에너지의 보급이 증가하면서 기존의 시스템과 신규 설치되는 시스템을 원격지에서 효율적으로 관리하는 모니터링 기술이 필수가 되었다 이들 모니터링 기술에는 발전 출력량과 기상조건 등의 복합적 요소 모니터링 기술이 필요하다. 다중 채널을 이용하여 모니터링 하는 기법은 통신속도와 S/W, H/W에 따라 각각여러가지 방법이 있으며 최대채널의 제한, 가격적인 부분까지 많은 부분을 고려해야 한다. 본 논문에서는 기존수행하고 있는 모니터링 기술을 분석하여 신재생에너지 시스템에 적합한 다중채널 모니터링 기법을 제안하고자한다.

• Journal of Information Technology Services
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• v.10 no.3
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• pp.1-19
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• 2011

The purpose of this study lies in enhancing an understanding of on-line collaboration among manufacturing companies for innovation. To meet this purpose, this study adopts Eisenhart(1989)'s case study approach to explore the success factors of on-line collaboration among Korean small-medium-sized manufacturing companies. Firstly, an exhaustive case study is conducted for four collaboration hubs in the Korean injection mold industry. This study identify the success factors through a structured questionnaire survey and in-depth interviews based on experts of K Institute, which performs the overall management of the collaboration hubs, and personnel of the participating businesses and vendors. Secondly, AHP analysis is conducted to identify the priorities among the success factors. Finally, several propositions of on-lin collaboration are derived.

• Journal of the Korean Society of Visualization
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• v.1 no.1
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• pp.75-81
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• 2003

A custom micro-PIV optics assembly has been used to measure the flow fold inside a T-junction of a microchannel. The micro-PIV system consists of microscope objectives of various magnifications, a dichroic cube, and an 8-bit CCD camera. Fluorescent particles of diameters 620 nm have been used with a Nd:YAG laser and color filters. A programmable syringe pump with Teflon tubings were used to inject particle-seeded distilled water into the channel at flow rates of 2.0, 4.0, 6.0 mL/hr. The micro-channels are fabricated with PDMS with a silicon mold, then O$_{2}$ -ion bonded onto a slide glass. Results show differences in flow characteristics and resolution according to fluid injection rates, and magnifications, respectively. The results include PIV data with vector-to-vector distances of 2 $\mu$m with 32 pixel-square interrogation windows at 50$\%$ overlap.

• Transactions of Materials Processing
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• v.20 no.3
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• pp.250-256
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• 2011

Vacuum-assisted thermoforming is one of the critical steps for the successful application of film insert molding(FIM) to parts of complex shapes. If the thickness distribution of the formed film is non-uniform, cracking, deformation, warping, and wrinkling can easily occur at the injection molding stage. In this study, the effects of processing parameters, which include the film heating time, plug depth, plug speed and vacuum delay time, on film thickness distribution were investigated. It was found that the film thickness at the part sidewall decreases with increasing the film heating time and plug depth, but the thickness at the bottom was found to exhibit the opposite behavior. The film thickness of the sidewall was observed to increase at higher plug speed and vacuum delay time of 0 ~ 0.3sec.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.865-870
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• 2004

This paper describes the generation of chordal surface for various shell structures, such as automobile bodies, plastic injection mold components and shell metal parts. After one-layered tetrahedral mesh is generated by an advancing front algorithm, the chordal surface is generated by cutting a tetrahedral element. It is generated one or two elements at a tetrahedral element and the chordal surface is composed with triangular or quadrilateral elements. This algorithm has been tested on several models with rib structure.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.948-957
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• 2003

금형산업은 ETO(engineer to order)방식의 산업으로서 각 주문마다 견적가를 책정하는 것이 손익에 큰 영향을 미치게 된다. 현재, 대부분의 금형업체에서는 금형주문에 대한 견적을 금형전문가의 개별적인 지식에 의존하고 있는데 이러한 방식은 주관적이며, 체계적이지 못한 문제점을 갖고 있다. 따라서 보다 합리적이고 체계적인 기준에 의한 견적가 결정 방법이 필요하다. 본 연구에서는 먼저 고객의 요구사항을 QFD(Quality Function Deployment)를 사용함으로써 금형제작에 있어서 원가에 영향을 미치는 요소를 추줄하게 된다. 이렇게 얻어진 금형제작 정보와 고객의 주문정보를 바탕으로 인공신경망, 사례기반주론 등의 인공지능 기법을 사용하여, 사출금형의 견적가를 책정하는 사출금형의 견적지원시스템을 개발하고자 한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.169-172
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• 2000

In this paper, an OMM (On-the-Machine Measuring) system has been developed, which can perform measuring and inspection of sculptured surfaces of die and mold, by use of a scanning-type touch probe mounted into the spindle of a NC machine. The calibration procedures of a scanning prove (SP2-1, Renishaw) and an algorithm for measuring surface points by a ball-nosed stylus have been studied. The system has been developed based on commercial CAM software (Z-Master 2000), and tested through measuring a plastic injection molding-die. Also some experimental results of the calibration and measuring for given surface positions are analyzed to verify its accuracy and reliability.