• 한국주조공학회지
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• 제4권2호
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• pp.102-107
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• 1984

The variations of the mold compression strength were studied by varing the contents of the silicon powder and water glass, silion purities, and molecule rates of the water glass, when domestic JA EUN DO sand is mixed with water glass (sodium silicate) and metallic silicon or ferro - silicon powder by the self - hardening N - PROCESS method. The results obtained from this experiment are as follows; 1) The compression strength of the mold used with metalic powder was higher and more stable than to be used ferro - silicon powder. 2) 6% water glass of 2.8 molecule rate and 1.5% of ferro - silicon of 75% purity for the N - PROCESS used with JA EUN DO sand was suitable mixing rate. 3) The compression strength increased with self - hardening time, and the PH values of the mixture of silicon powder and water glass did not change after 2 hours, but the compression strength increased steadily due to the reaction of remained silicon. 4) It is recommended to take 24 hours for self - hardening time at least.

• 한국전기전자재료학회논문지
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• 제19권11호
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• pp.1050-1054
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• 2006

There have been intensive and continuous efforts in the field of DLC coating process because of their feature, like high hardness, high elasticity, abrasion resistance and chemical stability and have been applied widely the industrial areas. In this research, optimal grinding condition was investigated using Microlens Process Machine for the development of aspheric glass lens which is to be used for mobile phone module with 3 mega pixel and 2.5X optical zoom, and tungsten carbide(WC) mold cote was manufactured using high performance ultra precision machining and the effects of DLC coating on the form accuracy(PV) and surface roughness(Ra) of WC mold core was evaluated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.191-192
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• 2006

• 한국재료학회지
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• 제31권6호
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• pp.331-338
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• 2021

Ti-Al-Si target and Cr-Si target are sputtered alternately to develop a multi-layered nitride coating on a steel mold to improve die-casting lifetime. Prior to the multi-layer deposition, a CrN layer is developed as a buffer layer on the mold to suppress the diffusion of reactive elements and enhance the cohesive strength of the multi-layer deposition. Approximately 50 nm CrSiN and TiAlSiN layers are deposited layer by layer, and form about three ㎛-thickness of multi-layered coating. From the observation of the uncoated and coated steel molds after the acceleration experiment of liquid metal injection casting, the uncoated mold is severely eroded by the adhesion of molten metallic glass. On the other hand, the multi-layer coating on the mold prevents element diffusion from the metallic glass and mold erosion during the experiment. The multi-layer structure of the coating transforms the nano-composite structured coating during the acceleration test. Since the nano-composite structure disrupts element diffusion to molten metallic glass, despite microstructure changes, the coating is not eroded by the 1,050 ℃ molten metallic glass.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.1199-1200
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• 2013

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.383-384
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• 2008

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1626-1631
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• 2007

The purpose of the study is to simulate the displacement of the LCD glass during process of a large size imprint. During this process, a small temperature variation makes thermal stress, which causes the horizontal variation of mold and glass. During alignment process to fix the LCD glass on a alignment stage, the vertical displacement is made by the absorption pressure and the shear stress. This study simulates the horizontal displacement of mold and glass due to temperature variation, the vertical displacement depending on the shape of absorption surface fixing the LCD glass in the alignment process, and the horizontal and vertical displacement which occurs in the LCD glass at the alignment process. Algor which is a FEM code for a framework simulation was applied. Temperature variation above ${\pm}$ $0.1^{\circ}C$ on mold and glass causes the horizontal displacement of 150nm due to thermal expansion. The vertical displacement due to the circular is ten times of the case of rectangular absorption nozzle. The displacement of the LCD glass in the alignment process is about 49nm.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.354-354
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• 2008

Recently, due to the tremendous growth of media technology, demands of the aspheric glass lens which is a high-performance and miniaturized is gradually increasing. Generally, the aspheric glass lens is manufactured by GMP(Grass Molding Press) method using WC(tungsten carbide) mold core. In this study, the thermal deformation which occurs in the cooling step of GMP was considered, and it was compensated the form of mold core. The lens which was molded by compensated mold core was satisfied that can be applied to the actual specifications.

• Transactions on Electrical and Electronic Materials
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• 제3권1호
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• pp.4-8
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• 2002

The typical mold method for FED (field emission display) fabrication is used to form a gate electrode, a gate oxide layer, and emitter tip after fabrication of a mold shape using wet-etching of Si substrate. However, in this study, new mold method using a side wall space structure was developed to make sharp emitter tips with the gate electrode. In new method, gate oxide layer and gate electrode layer were deposited on a Si wafer by LPCVD (low pressure chemical vapor deposition), and then BPSG (Boro phosphor silicate glass) thin film was deposited. After then, the BPSG thin film was flowed into the mold at high temperature in order to form a sharp mold structure. TiN was deposited as an emitter tip on it. The unfinished device was bonded to a glass substrate by anodic bonding techniques. The Si wafer was etched from backside by KOH-deionized water solution. Finally, the sharp field emitter array with gate electrode on the glass substrate was formed.

• 한국광학회지
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• 제18권5호
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• pp.362-366
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• 2007

본 연구에서는 3 메가픽셀, 2.5배 줌 카메라폰 모듈용 비구면 유리렌즈 개발을 목적으로 실험계획법(DOE)을 적용하여 성형용 초경 코어의 연삭가공조건을 구하고, 이를 활용하여 비구면 Glass렌즈 성형용 초경합금(WC) 코어를 초정밀 연삭가공을 수행하였다. 또한 가공된 성형용 코어의 가공면 위에 이온증착법으로 다이아몬드상 탄소(Diamond-Like Carbon; DLC) 코팅을 수행하여 DLC 코팅이 성형용 코어의 형상정도(PV)와 표면조도(Ra)에 미치는 영향을 평가하였으며, 비구면 Glass렌즈를 동일한 조건에서 성형하여 성형렌즈의 광학적 특성을 비교하여 성형용 코어면의 DLC 코팅 효과에 대하여 검토하였다.