• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.5 no.1
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• pp.17-26
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• 1996

In this paper, we have studied about the relationships between a core gap and a feeding velocity, an amplitude and the core gap by the exciting force, the parts movement and a bowl materials, and the feeding velocity and the weight of the parts in the parts feeder. The obtained are as follow : 1) Optimal condition of mean feeding velocity is speeded up largely when the core gap is in 0.6mm. 2) It can be safe to say that the relation between the feeding velocity and the exciting voltage relay on the core gap. 3) An exciting voltage is rised by an increase of the weight, but an amplitude has been in the range between 23$mu extrm{m}$ through 40${\mu}{\textrm}{m}$.

• Design & Manufacturing
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• v.7 no.1
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• pp.7-10
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• 2013

Pencil-core dies are relatively new technology in Korea. It is not that no one had tried to make them but had failed due to lack of technologies. However, Posco TMC Co., Ltd, one of the leading die makers in the world, is capable of sophisticated dies including pencil-core dies. Spark plugs made by pencil-core dies have energy efficiency close to 100 percent, which compares to 46 percent of conventional spark plugs. Even though they are now mostly installed in LPG automobiles, more and more diesel and gasoline vehicles are adopting them. This study focuses on how to improve core shape precision using controling design and parts machining methods for pencil-core dies and productivity.

• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.187-194
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• 2004

The study focused on setting priority among the future core technologies that were derived by Delphi in agricultural management ＆ information using analytic hierarchy process(AHP). Items for setting priority were decided as ‘technology’, ‘market’, and ‘public concerns’by council. The future core technologies were divided into four parts by importance and R＆D level. Technologies which consisted of upper two parts having higher importance were considered in the study. Questionnaires were given to 9 specialists in biosystems engineering. As the results, ‘market’ was decided as a most important item. The most important technologies were ‘Developing technology and system of post harvest processing for higher quality rice’ in group I, and ‘Developing sensor technology to evaluate quality and safety for agricultural products’ in group II.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.03a
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• pp.111-117
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• 1995

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.3
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• pp.82-87
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• 2019

Recently, plastic materials have become more diversified, and the development of materials with excellent mechanical properties and plasticity has enabled wider application, miniaturization, and refinement of injection molded products. As a result, the utilization of these products in household goods, electronics, automotive parts, and aircraft parts is increasing in almost all industries. Injection molded parts are often used externally on finished commercial products. This means that the injection mold industry is very important to the value of these products. For this reason, the industry is performing research on the precision and efficiency of the injection molding process. In this study, we investigated the applicability of the core in core cooling method to the problem of product deformation due to temperature variation in existing injection mold designs. We also characterized the cooling performance of an injection mold when using this cooling method.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.05a
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• pp.39-42
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• 2005

For mass production, usually injection mold has multi-cavity which is filled through geometrical balanced runner system. Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed. These filling imbalances are one of the most significant factors to affect quality of plastic parts when molding plastic parts in multi-cavity injection mold. Filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during injection molding processing. This paper presents a solution of these filling imbalances through using 'runner core pin'. The runner core pin which is developed in this study creates a symmetrical shear distribution within runner. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.5
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• pp.373-381
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• 2017

The electric vehicle market has increased rapidly in recent years. Established global automakers have announced that electric cars will be developed and distributed. Furthermore, current electric cars are not merely breezes, instead, they are the mainstream of automobiles. However, high prices, short mileage, and long charge times are the main obstacles to the spread of electric vehicles. To solve these problems, the competition for technology development for the expansion of electric vehicles worldwide intensifies because of the improvements in mileage, price reduction, and expansion of charging infrastructure. In this paper, the trends in the development of key technologies for electric vehicles in overseas markets and the present strategic goals for the development of key technologies for electric vehicles in Korea will be identified.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.13-16
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• 2005

For mass production, usually injection mold has multi-cavity which is filled through geometrical balanced runner system. Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed. These filing imbalances are one of the most significant factors to affect quality of plastic parts when molding plastic parts in multi-cavity injection mold. Filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during injection molding processing. This paper presents a solution of these filling imbalances through using 'runner core pin'. The runner core pin which is developed in this study creates a symmetrical shear distribution within runner. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.877-879
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• 1995

In this study, we developed the efficient brushless DC motor for a compressor of air conditioner. The characteristics of motor are under the control of the material of some parts and the shape of magnet. Especially we compared the interior shape to the surface shape of the magnet. And we optimized the parameters like the temperature and the materials of magnet and core by tool for more efficient motor.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.368-368
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• 2006

Micro-molded parts can be defined as parts with microgram weight, parts with micro-structured surface, and parts with micro-precision. In this study, various micro-scale molded parts for various polymers were produced by using a precision micro-molding machine. Molded parts with nano-structure surface were also produced to analyze the effect of molding conditions on replication of surface pattern and higher-order structure development of molded parts. Replication of molded parts was influenced by material properties, molding conditions and size of surface pattern. Higher-order structure of molded parts was investigated by using polarized microscope. Skin-shear-core regions inside the molded parts were observed and shear region affected to surface replication.