• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.629-630
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• 2009

• Design & Manufacturing
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• v.11 no.2
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• pp.1-8
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• 2017

In this study, we applied microcellular foaming injection molding process to improve the performance of system air-conditioner drain fan which had been produced by injection molding process and studied the optimization of process conditions through 6-sigma process and response surface method (RSM) to reduce weight and deformation of products. Additive type, melt temperature, mold temperature, and injection screw shape were selected as the factor affecting the weight and deformation of the products by carrying out analysis of trivial many through ANOVA and design of experiment (DOE) method. Among the effect factor, we set the addictive type to Long G/F and screw shape to foaming screw which had the highest level of weight reduction and deformation reduction. The amount of foaming agent gas was set at 60 ml, which was the limit beyond which the weight of product did not decrease any more. For melt temperature and mold temperature, we studied the conditions where both weight and deformation were minimized using the RSM. As a result, we set the melt temperature to $250^{\circ}C$, fixed mold temperature to $20^{\circ}C$, and moving mold temperature to $40^{\circ}C$. The improvement effect was analyzed by appling the selected optimal conditions to the production process using the microcellular foaming injection molding. The results showed that the mean weight of product was measured to be 1,420g which was 19% lower than that measured in the current process. The standard deviations of the weights were found to be similar to those in the current process and it showed a low dispersion. The mean deformation was measured to be 0.9237mm, which represented a 57% reduction compared to the mean deformation in the current process, and the standard deviation decreased from 0.3298mm to 0.1398mm. Moreover, we analyzed the process capability for deformation, and the results showed that the short-term process capability increased from 2.73 to 6.60 which was even higher than targeted level of 6.0.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1406-1409
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• 2003

There is a great demand for reducing the amount of material used in mass-produced plastics parts, for material cost constitutes a large percentage of the total cost of 60%. It may be noted that the price of plastics is directly rotated to the price of petroleum. Material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore microcellular foaming process(MCPs) was studied for solving this problems alternatively in 1980's at M.I.T Until now in MCPs carbon dioxide gas was mainly used for microcellular foaming. Besides, Talc was used for reducing the price of plastics. Consequently, we must certificate using the Talc in MCPs according to contents of the Talc.

• Design & Manufacturing
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• v.17 no.1
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• pp.64-69
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• 2023

This paper explores the impact of gate shape changes on the size and density of foamed cells in microcellular foam injection molding. Five different gate shapes were examined while varying the amount of nitrogen gas(N2) injected for foaming. Analysis of the results showed that while average values did not change significantly, deviation values decreased by approximately 65% for cell size and 56% for density when 3.5wt% of nitrogen gas was injected in the film gate. Further analysis was conducted to verify this phenomenon, revealing that the contact area between the gate and product had the greatest impact. Our findings indicate that to ensure uniform generation of foamed cells in microcellular foaming product design, a gate with a wide contact area should be secured.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.1
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• pp.195-200
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• 2001

There is a great demand for reducing the amount of material used in mass-produced plastics parts, for material cost constitutes up to 75% of the total production cost. Plastics do not easily decay which causes environmental problem. Furthermore, material reduction therefore decreases the amount of oil needed for the manufacture of plastics and thus help conserve this natural resource. Therefore, microcellular foamed plastics(MCPs) was developed at MIT to solve these problem alternation 1980's. Until now, however, microcellular foaming process not designed systematically because the key factors governing the process were not clear. The goal of this research is to obtain the optimal design of the microcellular plastics by using axiomatic approach.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.11-12
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• 2009

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1114-1119
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• 2004

In a foaming process of microcellular plastics (MCPs) with a injection molding, research on the viscosity change that occurs when the gas is injected to the polymer has received little attention despite its importance. The purpose of this paper is to provide the basic data required to determine the processing condition by measuring viscosity changes against the gas injection rates of the blowing agent, and to verify the influence of the viscosity change on the flow condition of polymer inside the mold at the injection process.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.228.1-228.1
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1211-1212
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.213-214
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• 2008