• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.50-57
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• 2016

Refrigerator glass shelves are manufactured by Insert Injection Molding. The current process of injection of glass into the mold induces movement of the core, on urethane springs. Defects in the product can result from too low a force being transmitted from the springs. To solve this problem, the force on the moving core and the injection molding pressure were subjected to numerical analysis. Based on this, the number of urethane springs as well as their hardness was changed to improve the situation. The number of springs was changed from 6 to 4. The diameter of the springs was increased from ${\emptyset}75$ to ${\emptyset}100$, and the hardness was increased from 70 (shore A) to 90 (shore A). These improvements caused the force on the molding core to increase by approximately 65,442 N. The proportion of defects decreased by 66%.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1029-1030
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• 2012

• Elastomers and Composites
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• v.35 no.2
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• pp.115-121
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• 2000

In comparison with thermosetting rubber, thermoplastic elastomer (TPE) has various advantages such as simple processing, short cycle time and recycling of scrap. These advantages can lead to development of the high value-added rubber products due to reduction of the waste material, manufacturing cost and the defected product. This article involves a dynamic vulcanization method for EPDM/polypropylene blend, and the manufacturing of a fixed glass weather-strip by glass insert molding method using the blend. In order to investigate mechanical properties of the product, tensile strength, elongation, hardness and specific gravity were measured. Also morphological study was carried out using SEM. Developments of an efficient system of production and automatic process by molding of TPE and glass simultaneously are expected.

• Design & Manufacturing
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• v.2 no.3
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• pp.6-9
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• 2008

This paper describes the process of structure analysis and injection molding analysis to manufacture the forming injection dies for huge glass insert. Factors such as filling time, filling pressure, material temperature, shrinkage, warpage were investigated by using the analysis software, Moldflow. Runner system and cavity structure were designed and manufactured through the results of deformation analysis data for glass insert. Filling time and filling pressure were analyzed in 3.756sec and 43.37MPa.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.23-28
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• 2005

Microlens arrays were fabricated using a modified LIGA process based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, the hot embossing and the microinjection molding processes have been successfully utilized with the fabricated mold insert. Fabricated microlenses showed good surface roughness than the mold insert. The focal lengths of the injection molded microlenses were successfully measured experimentally and also estimated theoretically.

• Composites Research
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• v.25 no.4
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• pp.117-125
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• 2012

Warpage of the film insert molded (FIM) part is caused by an asymmetric residual stress distribution. Asymmetric residual stress and temperature distribution is generated by the retarded heat transfer in the perpendicular direction to the attached film surface. Since warpage was not prevented by controlling injection molding conditions, glass fiber (GF) filled composites were employed as substrates for film insert molding to minimize the warpage. Distribution of short GFs was evaluated by using micro-CT equipment. Proper models for micro mechanics, anisotropic thermal expansion coefficients, and closure approximation should be selected in order to calculate fiber orientation tensor and warpage of the FIM part with the composite substrate. After six kinds of micro mechanics models, three models of the thermal expansion coefficient and five models of the closure approximation had been considered, the Mori-Tanaka model, the Rosen and Hashin model, and the third orthotropic closure approximation were selected in this study. The numerically predicted results on fiber orientation tensor and warpage were in good agreement with experimental results and effects of GF reinforcement on warpage of the FIM composite specimen were identified by the numerical results.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.34-41
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• 2006

Microlens arrays were fabricated by a modified LIGA process composed of the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, both hot embossing and microinjection molding processes have been successfully utilized with the fabricated mold insert. Replicated microlenses showed very good surface roughness with the order of 1 nm. The focal lengths of the injection molded microlenses were successfully estimated theoretically and also measured experimentally.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.1
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• pp.18-24
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• 2010

Efforts to obtain more efficient coupling of light from a laser diode to a single mode fiber have continued for various applications such as links for optical fiber communication systems. In TO-can package, configuration of optimized aspherical lens is bi-aspheric and its diameter is 2.4mm. We designed and fabricated aspherical coupling lens by means of glass molding technique under consideration of glass shrinkage. By controlling the aspherical profile error and surface roughness which were below 90nm and 10nm, respectively, we obtained the low coupling loss, 5.40dB, which was able to use for coupling a single mode fiber to laser diode.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.206-210
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• 1989

In automobile glass fitting the stud is welded on the window seating panel in order to insert the plastic molding onto the stud. Since this type of process is in general manually done, almost 50% of the output turns out to be failure resulted from work inefficiency and weld inferiority. Therefore, it is required to improve this process for the productivity elevation through the application of the robot.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.32-38
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• 1998

In order to investigate the relationship between the stiffness and structure of the automotive roof panels, two kinds of glass fiber reinforced plastic(GFRP) roof panels without and with insert material were fabricated by resin transfer molding(RTM) method. The stiffness test was performed at the same condition as it of actual driving. The structural design and material selection for improving the recyclability of GFRP roof panels were also covered.