• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5352-5356
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• 2013

Plastic product manufacturing industry has usually focused on a mechanical and physical characteristics of molding. Recently, not only these characteristics but also the aesthetic value is significantly considering. Especially, the molding's gloss, which we can easily distinguish, is an important aesthetic point. In this study, it were investigated that the gloss variation of ABS moldings by changing injection conditions such as injection pressures, injection speed, holding pressures melt and mold temperatures by injection molding experiment. The experimental results revealed that the holding pressure was the most active condition on gloss of ABS molding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.882-885
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• 2002

Magnesium alloys are very attractive materials for appling to the development of autemobile parts or electric goods where light weight and higher stiffness. Due to higher ratio of strength vs. weight and stillness vs. weight, various magnesium alloys are well applied in much weight saving design applications though extrusion or die-casting process. However for the requisites of higher strength and weight savings, some new fabrication processes has been and it can be realized though the aid of injection modeling technology. To obtain the parametric data base for the injection molding process, various experiments were executed for AZ91D magnesium alloy. This paper propose the optimum condition of injection temperature, first and second pressure. the process was lined-up successfully often changing the injection unit. fluid pressure system from the conventional plastic injection molding process.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.833-836
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• 1997

Magnesium alloys are one of light weight material. Strength and stiffness of Magnesium alloys are enough to use for commercial product. Demand for strong, lightweight parts several computer and electronics have driven much of Magnesium injection molding's growth so far. And it is eighth most abundant resource on earth. In electronic device, electromagnetic interface and electrostatic discharge can affect performance. Magnesium injection molding is similar to normal plastic injection molding process. But some process condition is different. Especially injection speed and process temperature are so differs from other injection molding system. It just start for make something. But Magnesium injection molding is one of best alternate process for producing metal alloy part.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.357-358
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• 2006

Importance of using an injection molding analysis has been increased. However the application of it has not been increased because the results of analysis do not sometime match to practical molding. Therefore, the difference of flow analysis and practical molding should be decreased. This study presents reasons of the difference for the location of weld-line in the flow analysis and practical molding on automobile bumper molding.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.8
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• pp.573-581
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• 2022

This paper deals with the development of CanSat system, which ejects two maple seed-type autorotating science payloads and collects weather information. The CanSat consists of two autorotating science payloads and a container. The container is equipped with devices for launching science payloads and communication with the ground station, and launches science payloads one by one at different designated altitudes. The science payload consists of a space for loading and a large wing, and rotates to generate lift for slowing down the fall speed. Specifically, after being ejected, it descends at a speed of 20 m/s or less, measures the rotation rate, atmospheric pressure, and temperature, and transmits the measured value to the container at a rate of once per second. The communication system is a master-slave structure, and the science payload transmits all data to the master container, which aggregates both the received data and its own data, and transmits it to the ground station. All telemetry can be checked in real time using the ground station software developed in-house. A simulation was performed in the simulation environment, and the performance of the CanSat system that satisfies the mission requirements was confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1040-1046
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• 2006

This paper is aimed to investigate the deformation caused by ununiform contraction of injection molding with highly big differences of thickness by the continuity of various curvature radius. By CAE analysis, the uniform cooling structure and optimum molding conditions are found for Jars made of SAN and PMMA materials and applied to the design of chill. In order toevaluate the molding pressure, resin temperature, molding temperature, cooling conditions, Moldflow program is applied. As results of experiments, the deformation and inferiority phenomena in Jars are analyzed for each factor and proposed the injection molding conditions to minimize the cooling structure and reduce the cycle time.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.10a
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• pp.443-444
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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.503-504
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.131-131
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• 2004

최근 정보량의 증가와 통신속도의 증가로 인해 광 저장매체의 용량 증가에 대한 요구가 급증하고 있다. 광 저장매체의 용량을 증가시키기 위해서는 광 저장매체의 최소 피치 크기를 줄이는 방법으로 가능해진다. 기존의 광 저장매체에 대한 패턴 식각 기술은 광을 이용한 노광 기술로 이루어져 왔다. 그러나 광을 이용한 노광 기술은 광 굴절에 의한 한계로 인해 500nm이하의 패턴을 형성하는데 많은 어려움이 따른다.(중략)

• Clean Technology
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• v.11 no.4
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• pp.205-211
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• 2005

There have been many technologies and materials proposed for realizing microlens array, and plastic injection is recognized as the most promising one because of several merits such as optical properties, impact resistance, formability, lightening and environmental adaptability. Since PR reflow for injection template fabrication enables the lens shape control easier, and the sample technology more effective for mass production, it lowers the cost, enhances integration, and reduces process steps, which leads to be environmentally benign. However injection of polymers may face the difficulty of formability depending on their properties. In order to overcome the difficulty, fast heating/cooling technology was introduced in this study, and microlenses were fabricated and evaluated. template obtained by PR reflow method was heated and cooled fast during injection to fabricate microlens array. PC and PMMA polymer materials were compared, and it was realized that PMMA showed much better formability due to its lower melting temperature. Injection parameters of pressures and velocities were driven out for injection optimization.