• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.41-45
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• 2006

In recent years, the demands of the aspheric glass lenses increase since it is difficult to obtain the desirable performance in the plastic lens. Glass lens is manufactured by the forming with high precision mold core. This paper presents the analysis of optimal grinding condition of tungsten carbide(WC, Co 0.5%) using design of experiments(DOE). The process parameters are turbin spindle, work spindle, feedrate and depth of cut. The experiments results are evaluated by MINITAB software.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.168-174
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• 2007

A ceramic glass mold was developed for micro hot-embossing and replicated polymer parts are fabricated. The glass-ceramic micro mold could be fabricated with a laser process and a wet etching process and the fabrication time could be saved a lot. Various polymer micro structures can be obtained by hot-embossing. The process parameters such as ho-embossing temperatures or pressures were investigated and optimized. This process can be applied for fabrication of micro structures for flip-chips or micro fluidic channels for bio-engineering. The advantages and disadvantages of this process are discussed, too.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2018.05a
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• pp.214-215
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• 2018

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.315-316
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.217-218
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• 2010

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.7
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• pp.952-957
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• 2001

In the glass forming process, the phenomena of hyperbolic heat conduction in the hot mold with an inner defect are studied analytically. It is shown that the temperature predicted by the parabolic model is underestimated compared to the one by the hyperbolic model. As the rmal wave is reflected from the area with defects and then arrives at the surface supplied by the heat flux, it is expected that there exists thermal shock in the materials. The area with defects is assumed to be adiabatic since its thermal conductivity is much lower compared to the one of the material. The results also indicate that the sudden temperature -jump in the mold surface can cause diverse problems such as glass defect (embryo mark, etc), oxidation of mold and coating, and change of material properties.

• Korean Journal of Metals and Materials
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• v.50 no.8
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• pp.591-597
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• 2012

This paper presents regularly micro-textured glass surfaces ensuring the superhydrophobic properties in the Cassie-Baxter regime. The proposed surfaces were fabricated simply and efficiently by filling the glass material into a silicon micro-mold with periodic micro-cavities based on a thermal-reflow process, resulting in a successful demonstration of the textured glass surface with periodically-arrayed micro-pillar structures. The static and dynamic wetting properties of the micro-textured glass surfaces were characterized by measuring the static contact angle (SCA) and contact angle hysteresis (CAH), respectively. In addition, the surface wettability was estimated theoretically based on Wenzel and Cassie-Baxter wetting theories, and compared with the experimental ones. Through the experimental and theoretical observations, it was clearly confirmed that the proposed micro-textured glass surfaces showed the slippery superhydrophobic behaviors in the Cassie-Baxter wetting mode.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.3
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• pp.261-265
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• 2012

In this study, glassy carbon was ground for lens core of glass mold press. Ultraprecision grinding process was applied for machining of core surfaces. During the process, brittle crack occurred because of hard-brittleness of glassy carbon. Author investigated optimized grinding conditions from the viewpoint of ductile mode grinding. Geometrical undeformed chip thickness was adopted for critical chip thickness that enables crack free surface. Machined cores are utilized for biaspheric glass lens fabrication and surfaces of lens were compared for verification of ground surface.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.91-96
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• 2000

Glass fiber reinforced thermoplastic composites were manufactured by Rapid Press Consolidation Technique(RPCT) as functions of temperature, pressure and time in pre-heating, consolidation and solidification sections during the manufacturing processing. It was found that the material property is greatly affected by pre-heating temperature under vacuum, mold temperature and molding pressure. Among them, the temperature In the mold was the most critical factor in determining the mechanical properties and the molded conditions of specimen. The crystallinity of PET matrix was also investigated by differential scanning calorimetry(DSC) measurements for various processing conditions. The level of crystallinity($X_c$) depended strongly on the mold temperature, cooling rate and the type of composite. The difference in $X_c$ is believed to be one of important factors in characterizing the mechanical properties.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.556-561
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• 2007

The rapid thermal response(RTR) molding is a novel process developed to raise the temperature of mold surface rapidly in the injection stage and then cool rapidly to the ejection temperature by air or water. The objectives of this paper are to investigate the effect of mold temperature, pressure and thickness of micro pattern molding and to provide a optimization of RTR injection molding for micro pattern from Moldflow simulation. Optimal minimum temperature and pressure was found without shortcut according to thickness. Filling percentage was influenced by glass transition temperature with the kinds of resin. Optimal temperature is slightly higher than glass transition temperature irrespectively of pressure, thickness, the kinds of resin in the micro pattern molding.