• Proceedings of the KSME Conference
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• 2002.08a
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• pp.423-426
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• 2002

A custom micro-PIV optics assembly has been used to measure the flow field inside a T-shaped 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 620nm 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 $420,\;40,\;60{\mu}L/hr$. The microchannels 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 show PIV results with vector-to-vector distances of $2{\mu}m$ with 32 pixel-square interrogation windows at $50{\%}$ overlap.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1394-1397
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• 2003

The first thing in developing injection molding and extrusion with microcellular foaming process is to get a grip on one phase state's rheology of gas and polymer solution. Understanding rheology is essential to design mold or die. and it is so important to control the condition of process. Also, this data is got the utmost out of simulation carrying out. In this paper, we will see the measurement of rheology in one phase that mixed polypropylene which contains talc with carbon dioxide of super critical fluid state, and will compare its result with the simulation result.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.6
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• pp.30-35
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• 2009

• The Korean Journal of Rheology
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• v.3 no.2
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• pp.124-134
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• 1991

세라믹 재료들을 성공적으로 사출성형하기 위한 적절한 사출조건을 얻기 위하여 그 동안 많은 실험을 하여 왔으나 게이트 크기가 미치는 영향에 대한 연구는 미진하였다. 본 연구에선 압출기를 사용하여 미세한 질화규소분말과 결합제시스템을 혼합하였으며 이러한 세라믹혼합물을 이용하여 사출압력, 보압시간, 보압, 배럴온도, 게이트의 형태와 크기 등을 변화시키면서 사출성형 실험을 수행하였다. 55%의 세라믹혼합물을 사출실험한 결과 적절한 게이트의 크기와 형태를 선택하고 105 MPa의 사출압력과 10초의 보압시간, 24$0^{\circ}C$의 배럴온 도와 같은 사출조건하에서 성형한다면 불완전 충전 체적수축과 젯팅현상을 최소화시킬수 있 어 성공적으로 인장시편과 굽힘시편을 성형할 수 있음을 알수있었다. 상용프로그램인 C-MOLD를 이용하여 사출조건과 게이트의 크기를 변화시키면서 혼합물의 유동특성을 해석 하였다. 유동해석 결과. 세라믹혼합물은 순수고분자보다 열전도도가 크고 비열이 작아서 고 화가 빨리 되므로 게이트의 크기는 사출압력, 배럴온도와 같은 사출조건과 더불어 중요한 사풀변수임을 예측할 수 있었다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.3-10
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• 2002

In this study on machine measuring system based on solid feature was developed. This system was applied with injection mold using 3 dimensional solid modeler for verification. Developed program include pre-processor, main processor, and post processor. In pre-processor there are functions which check intersection, simulate motion of probe and calculate measuring time. Main processor generates measuring path and output NC code in Unigraphics. In post-processor functions that include evaluation of undercut or overcut and display of measuring procedure are offered. In addition analysis module for quality control of measured data on manufactured product was developed with geometric and dimensional tolerance concept. As the result developed program could get stability of system, precision of product, rapidity and cost down of manufacturing process compared with before measuring process.

• International Journal of Precision Engineering and Manufacturing
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• v.6 no.2
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• pp.12-18
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• 2005

A geometric compensation of thin-walled molded parts in reverse engineering is presented. Researches in reverse engineering have focused on the fitting of points to curves and surfaces. However, the reconstructed model is not the geometric model because the molded parts have some dimensional errors in measurements and deformation during molding. Geometric information can give an improved accuracy in reverse engineering. Thus, measurement data must be compensated with geometric information to reconstruct the mathematical model. The functional and geometric concepts of the part can be derived from geometric information. LSM (Least square method) is adopted to determine the geometric information. Also, an example of geometric compensation is given to improve the accuracy of geometric model and to inspect the reconstructed model.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.974-977
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• 2010

본 논문은 자동차의 부품 중 에어 밴트를 효율적으로 개발하기 위하여 제품의 형상, 사출 해석, 변형과 그 제품이 완성차에 설치 시 열유동에 관한 해석 및 개발에 관한 논문이다. 이를 위하여 3차원 설계를 한 후, 사출성형 공정에 대한 충전시간, 웰드 라인, 에어트랩 등 사출 성형 공정에 대한 분석 하였다. 다음으로 완성차에 조립된 상태에서 열유동 해석을 통하여 제품 윤곽선의 적합성을 확립하였으며 이를 바탕으로 하여 금형을 제작할 수 있는 설계조건을 확립 하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.209-210
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• 2014

사출금형은 자동차의 경량화 요구에 따라 일반 엔지니어링 플라스틱에서 고강도 플라스틱 성형을 위한 사용 환경으로 변해가고 있다. 이에, 사출금형의 표면은 마모에 대한 내력을 갖는 고경도 특성과 수지의 유동성을 양호하게 하기 위한 저마찰 특성의 요구가 점차 증가하고 있다. 본 연구는 사출금형 소재 표면의 고경도 저마찰 특성 부여를 위하여 대형 플라즈마 표면처리 공정을 이용하여 각각 질화처리와 비정질 탄소 코팅 공정기술에 관한 연구를 수행하였다. 각각의 플라즈마 처리된 샘플은 표면처리 공정 변수에 따른 경도 및 마찰계수 평가를 통하여 사출금형 소재 표면의 물리적 특성 변화를 관찰하였다.

• Journal of the Korea Safety Management & Science
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• v.13 no.4
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• pp.101-108
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• 2011

In this paper deals with strength of glass fiber reinforced plastics produced by shouting machine was investigated by universal testing instrument. We can obtain following results by performing the strength evaluation of polymer composite material according as varied environment temperature. The effect of environmental temperature on Strength properties was more sensitive in the weld specimen than parent. When changed environmental temperature, variation of strength in the parent was much bigger than it of weld specimen, that is, matrix in the parent, orientation in the specimen ware more sensitive to environmental strength. Tensile strength of polycarbonate matrix was similar regardless of mold temperature.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.253-256
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• 2000

In order to commercialize the low cost composite fabrication technology in the area of domestic aerospace structure field, Resin Transfer Molding process has been considered as an alternative process to replace the high cost autoclave technology. The end part for the development of RTM process is the control rod of flight control system of aircraft. A braided preform was triaxially designed to improve the dimensional stability and mechanical property in the direction of external loads. Through the flow analysis using CVFEM, the resin filling time was calculated and the resin injection method was determined. The results of the flow analysis were directly applied to RTM mold design. The control rod was successfully manufactured by RTM process using internal pressure. The length and outer diameter of the manufactured part are 1148mm and 32mm, respectively.