• Design & Manufacturing
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• v.8 no.1
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• pp.40-44
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• 2014

As a rotating machine element, plastic gears are more and more widely used in such as industrial machine element, since plastic gear is lighter, higher wear-resistance, and higher vibration absorbing ability than metal gears. When operating plastic parts, tooth breakage and fatigue life shortened due to increasing number of applying load and tooth flank temperature rising, such that accuracy of plastic gears is divided from allowable range to cause vibration and noise. On this study, a internal plastic gears are developed which improved the filling balance molding process by a new injection mold structure. The new mold structure called HR3P(hot runner type 3plate mold). As the result from this studies, we obtained a very accurate roundness internal gears by using design of experiment.

• 한국금형공학회:학술대회논문집
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• 2008.06a
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• pp.129-133
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• 2008

As a rotating machine element, plastic gears are more and more widely used in such as industrial machine element, since plastic gear is lighter, higher wear-resistance, and higher vibration absorbing ability than metal gears. When operating plastic parts, tooth breakage and fatigue life shortened due to increasing number of applying load and tooth flank temperature rising, such that accuracy of plastic gears is divided from allowable range to cause vibration and noise. On this study, a internal plastic gears are developed which improved the filling balance molding process by a new injection mold structure. The new mold structure called HR3P(hot runner type 3plate mold). As the result from this studies, we obtained a very accurate roundness internal gears by using design of experiment.

• Design & Manufacturing
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• v.2 no.2
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• pp.33-37
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• 2008

This paper describes the optimization of injection molding conditions to minimize sink marks. Sink marks, which refer to a small depression on the surface opposite a thick wall thickness, are often encounted in injection molded plastic parts. Part geometry, material properties and processing conditions during injection molding can affect the sink mark depth. We designed the runner system which is possible balanced filling to cavities using CAE program and then obtained optimal processing conditions by Taguchi's Robust Design technique. By actual injection molding using optimized mold and molding conditions, it confirmed that sink mark depth decreased zero compared to 1mm level in the conventional mold and process.

• (The)Study of the Eastern Classic
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• no.57
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• pp.407-435
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• 2014

Gusadang Kim, Nak-Haeng is a scholar of 18th century in Yeongnam region who wrote about 130 Chinese poems. In this study, I searched Gusadang's inner world by interpreting his Chinese poems. His life is closely related to his father Jesan Kim, Seong-Tak who was exiled. The fact that he devoted himself to his father for 10 years shows he had strong standards in making decisions in life. In short, Gusadang was a person who looked gentle but was tough inside and he remained firm in his faith even with outside pressure. He could not achieve glory because he spent time serving his father in his thirties. Although he heard compliments from others that he was talented enough to succeed as a scholar, he lacked time and mental energy to study. Also, he was a moralist and wrote some poems about impressive events in his life even though he did not fully devote himself to writing poems. In this study, I searched his inner world focusing on how he felt and thought about outside world by analyzing his poems. In conclusion, I found three characteristics from his poems. Firstly, depressed feelings are shown based on excessive self-consciousness in the poems related to his father. Secondly, his will to keep balance in life is shown because he wanted a harmonious life as a seeker after truth. Thirdly, a sense of isolation is shown because he had to keep a distance from outside world.

• Design & Manufacturing
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• v.8 no.1
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• pp.10-13
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• 2014

Plastic products are producted more than 70% of total processes by the injection molding. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. It spends most of times in the cooling process. Therefore, it is important to control the mold temperature in producing plastic products. The time and system of cooling affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. This study shows comparative study about cooling efficiency of spiral channel and baffle and observed the variation of time to freeze of molding As the result of CAE experiments, cooling rate by spiral channel had faster than baffle and as freeze time was decreased. Results of this study will be used widely to design for cooling system of injection mold.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.38-46
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• 2020

The purpose is to evaluate the structural characteristics of 750 mm diameter injection spiral blades under various operating conditions. A fiber-glass reinforced polypropylene material was employed to the injection blades, and mechanical tests on two kinds of glass-reinforced polypropylene were performed to evaluate the mechanical properties and to select a suitable candidate material. Also, three kinds of spiral blade geometries were studied to observe the influence of fixing rods between blades. For this, structural analyses were conducted to understand the role of fixing rods under a range of rotating speed. In addition, modal analysis was performed to confirm the resonance in the operating speed range. One-way fluid-structure interaction (FSI) analysis was carried out to know its mechanical integrity under dangerous wind speed conditions. Through this work, the structural characteristics of the proposed spiral blade geometries were studied under various operating conditions, and the requirements of mechanical properties of blades were determined.