• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.6
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• pp.961-967
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• 2012

The metal is frequently used in the air-conditioner frame, which must have the durability from the various external environments, but has difficulties in being manufactured for many complex shapes. On the other hand, the plastic, used as a material of injection molding, enables the realization of various shapes and the mass-production of complex ones and leads low production cost. As the air-conditioner frame becomes increasingly complex and detailed, the plastic material is highlighted as an alternative for the frame. But the product molded by plastic with a complex shape might have a noise problem. Therefore this study attempts to design the product through TRIZ in order to reduce the noise of the air-conditioner with the frame of plastic material.

• International Journal of Precision Engineering and Manufacturing
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• v.7 no.4
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• pp.23-27
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• 2006

Rubber is used in many industrial products, such as hoses, rubber belts, and oil seals. In particular, more than 200 rubber parts are used in automobiles. The design technology of these parts is largely dependent on field experience, which leads to lengthy and expensive developing procedures. However, with the help of recent developments in nonlinear computer analysis, new rubber products can be developed at low cost. In this study, rubber injection molding design variables, such as location and number of gates, were optimized using computer-aided engineering with the cross-WLF equation to produce CLIP rubber products made from ethylene propylene diene monomer(EPDM). The validity of the proposed design was evaluated by comparison with actual forming results.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.603-607
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• 2002

Cavity pressure is a factor of what is occurring inside the mold and is used as one of the process parameters that control the overall injection molding cycle. The insight of cavity pressure is able to predict part quality and optimum process condition. In this paper, it is adapted ejector pin sensor to measure the cavity pressure and investigates the flow balance and the cavity pressure according to different runner thickness for adjusting the flow balance. Flow balance is very important to have not the poor results such as flash and warpage in the family mold. This paper predicted flow balance and cavity pressure using CAE analysis tool and compared with the test results. The results of analysis and test have a good agreement with the cavity pressure profile and flow pattern of the test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.51-51
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• 2004

렌즈는 광학제품의 성능에 직접적인 영향을 미치는 주요 부품으로서, 고정도의 형상 및 안정된 내부물성을 요구하는 정밀 부품이다. 광학 렌즈는 특정 광학계 내에서 입사광이 원하는 위치에 초점을 맺을 수 있도록 굴절시켜주는 역할을 하며, 이를 위해 초점거리, 배율, 렌즈의 성능 등을 종합적으로 고려하여 렌즈의 형상을 설계해야 한다. 이러한 설계과정은 기하광학에 기반한 광선추적(Ray tracing) 기법을 통해 이루어지며, 주로 CodeV, OSLO 등의 상용 광학계설계 소프트웨어를 사용하여 수행되고 있다.(중략)

• Journal of Korean Society for Quality Management
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• v.33 no.1
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• pp.64-72
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• 2005

The ever increasing demand for enhanced competitiveness of engineered products requires "designing-in-quality" strategies that can effectively and efficiently incorporate concepts of uncertainty and quality into design. Multi-attribute utility function is commonly used to represent the decision-maker's preference on multiple design attributes under conditions of uncertainty and risk. One of the major issues in implementing this approach concerns the generation of appropriate utility function, especially in a complex engineering design environment. Typically, the decision maker's preference is revealed through lottery questions rather than being structured on the deductive reasoning to reflect the nonlinear tradeoffs among the attributes. The use of such intuitive procedures can lead to inexact preference information that may result in inaccuracy and rank reversal problems. This paper presents an alternative procedure based on the pair-wise comparisons between design alternatives towards a consistent preference presentation in assessing multiplicative utility function. The effectiveness of the overall procedures is tested with the aid of an injection-molding process design for a capacitor can and the results are discussed.

• The Korean Journal of Rheology
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• v.6 no.2
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• pp.104-118
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• 1994

단섬유 보강 플래스틱 재료의 사출성형 충전공정에서 금형재의 유동장이 섬유 배향 상태를 형성하는데 중요한 역할을 할 뿐만 아니라 섬유의 배향상태가 역으로 유동장에 영향 을 미친다. 충전유동과 섬유 배향의 연계해석을 위하여 단섬유에 의한 추가적인 응력을 포 함하는 Dinh과 Armstrong의 이방성 구성방정식을 충전유동의 해석에 도입하였다. 평명방향 으로의 속도구배에 의한 응력을 고려하여 새롭게 유도된 압력 지배방정식과 에너지방정식을 유한요소법과 유한차분법을 이용하여 풀고 동시에 2차배향텐서의 변화방정식을 4차 Runge-kutta 방법을 이용하여 풀었다. 절점 게이트 주변의 확장유동영역과 라인게이트를 통한 수축유동영역에서 평면방향으로의 속도구배에 의한 응력이 유동장에 미치는 영향을 고 찰하였다. 확장유동영역에서는 평면방향으로의 속도구배에 의한 영향이 추가적인 유량으로 나타나면서 주어진 유량조건하에서 평면방향으로의 속도구배에 의한 응력을 고려하지 않은 경우보다 작은 압력구배를 나타냈다. 수축유동영역에서는 위와 반대의 결과를 보였다. 이러 한 경향은 섬유의 부피분율이증가하거나 모양비가 커짐에 따라 증가한다.

• The Korean Journal of Rheology
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• v.9 no.4
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• pp.190-199
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• 1997

단열용도의 폴리우레탄 미세포 포움의 가공에 대한 연구를 수행하였다. 미세포 구조 를 얻기 위해서는 핵생성율을 증진시키고 균일한 분포의 기포를 생성시켜야 한다. 이를 위 해 이산화탄소 기체를 풀리올과 이소시아네이트에 각각 과포화시키고 충돌혼합하여 초음파 가진을 적용하였다. 이산화탄소 기체가 수지 내부에서 기포 내부로 확산함에 따라 기포의 성장이 조절된다고 가정하고 금형이 충전되는 동안에 금형 내부에서의 기포성장기구를 이해 하기 위하여 수치적인 방법으로 이론적 연구를 수행하였다. 경화 시간과 확산 경계를 고려 하여 최종적인 기포의 크기를 계산하였으며 반응속도론을 고려하여 중합반응동안의 폴리우 레탄의 점도의 변화를 예측하고 경화 시간을 결정하였다. 실험적으로 결정된 기체 분자수를 기준으로 하여 이론적으로 확산경계를 예측하였다. 화학적 발포제인 물과 함께 물리적 발포 제인 이산화탄소를 각각 1,2,3기압의 포화압력으로 변화시키면서 폴리올과 이소시아네이트에 포화시켜 폴리우레탄 포움을 제작하고 제작된 포움의 밀도, 열전도도, 및 기포의 수와 지름 을 측정하였다. 측정된 결과로부터 이산화탄소의 포화압력과 초음파 가진이 포움의 기포핵 생성에 미치는 영향을 살펴보았다.

• Journal of Powder Materials
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• v.14 no.6
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• pp.410-414
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• 2007

Carbon contamination from the binder resin is an inherent problem with the metal powder injection molding process. Residual carbon in the W-Cu compacts has a strong impact on the thermal and electric properties. In this study, uncertainty was quantified to evaluate determination of carbon in a W-15%Cu MIM body by the combustition method. For a valid generalization about this evaluation, uncertainty scheme applied even to the repeatability as well as the uncertainty sources of each analyse step and quality appraisal sources. As a result, the concentration of carbon in the W-Cu part were measured as 0.062% with expanded uncertainty of 0.003% at 95% level. This evaluation example may be useful to uncertainty evaluation for other MIM products.

• Journal of Sensor Science and Technology
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• v.18 no.6
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• pp.441-448
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• 2009

Magnesia partially stabilized zirconia(Mg-PSZ) solid electrolytes for an improvement of thermal shock resistance, which is suitable for the measurement of oxygen activity in a molten steel, were prepared by post-thermal aging treatment. The steelmaking oxygen sensor elements were formed by an injection molding method, sintered at $1650^{\circ}C$, and then thermal aged ranged from 1250 to $1400^{\circ}C$. Sintered density and porosity were decreased as increasing the magnesia content in a zirconia-magnesia solid solution. Fractions of cubic phase to the synthesized Mg-PSZ solid electrolytes were ranged from 13.13 to 79.54.% after post-thermal aging treatment. Very dense microstructure without voids in the grains was obtained by the post-thermal aging process. Fine tetragonal phase crystallites precipitated on the cubic surface during post-thermal aging up to $1300^{\circ}C$ improve a thermal shock resistance and reappearance of electro motive force(EMF) curve.

• Journal of the Korean Society of Industry Convergence
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• v.12 no.1
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• pp.35-42
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• 2009

In Taguchi's quadratic expected loss function used as robustness metric of performance characteristics, the mean and variance contributions are confounded. The consolidation of the mean and variance in the expected loss function may not always be the ideal approach. This paper presents a procedure for multi-attributes design optimization, where the mean and variance of performance characteristics are considered as separate attributes having designer's relative preferences for them and Technique for Order Preference by Similarity to Ideal Solution(TOPSIS) is introduced to attain robust optimal design. The effectiveness of proposed approach is shown with an example of a weld line minimization problem in the injection molding process.