• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.141-146
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• 2005

In the present study, the characteristic of warpage and flow balance for family mould, which is able to mold parts with different shapes in a mold, is considered. To obtain an optimal gate and runner system, plastic injection molding analysis with commercial code is performed. Design and manufacturing of family mould is then carried out on the basis of this computer aided engineering result. Flow balance and warpage comparisons between experiment and numerical analysis give good agreement with each other. However, it was shown that results of warpage measured by CMM was about $20\~55\%$ lower than those of numerical analysis.

• Design & Manufacturing
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• v.6 no.1
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• pp.1-4
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• 2012

Plastic products are producted more than 70% of total processes in 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. In this study, it was made a comparative study about cooling of linear channels and baffles and observed the variation of mold temperature on the coolant's temperature. As the result, the linear channel's cooling rate had faster than baffles and as coolant's temperature was increased, difference of cooling time was increased. Result of this study will be used widely to design for cooling system of injection mold.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.6
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• pp.1933-1947
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• 1991

The synthesis of supplementary features of injection molded parts has been done empirically, since it requires profound knowledge about the features' moldability and causal effects on the properties of the part, which are not available to designers through current CAD systems. RIBBER is a knowledge module which contains knowledge to permit non-experts as well as mold design experts to generate acceptable supplementary features of injection molded parts. A knowledge-based CAD system is constructed by adding the knowledge module, RIBBER, for mold feature synthesis and appropriate CAE programs for mold design analysis to an existing geometric modeler in order to provide designers, at the initial design stage, with comprehensive process knowledge-based CAD system is a new tool which enables the concurrent design and CIM with integrated and balanced design decisions at the initial design stage of injection molding.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.1
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• pp.105-110
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• 2015

In this study, a high-speed procedure to be used in composite molding technology is developed for the production of a hybrid supercapacitor in a progressive and revolutionary current in a production system, as are the related operating conditions. Mold parts with solid modeling, the ease of programming of future mold product designs, tolerance management, and pre-explode tests by the building of a progressive die design system using Cimatron_E10 Die Design Software for the strip layout are done. The capacity of the super-hybrid composite mold design will save time and money through its verification of the manufacture of molds. We plan to apply this to future related products for production cost savings of more than 30% achieved by considering the components of the production costs, labor, and material costs of production as compared to conventional production methods.

• Elastomers and Composites
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• v.48 no.4
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• pp.300-305
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• 2013

Part shrinkage in injection molding is inevitable phenomenon. Thus, it is necessary not only study on the reducing part shrinkage but characterization of part shrinkage. In this study, part shrinkage in injection molded 2.5 dimensional annular shaped specimens has been studied using glass fiber reinforced PC. Annular shaped specimens were designed with various sizes of outer diameter and thickness. Injection temperature, packing time and packing pressure were selected for operational conditions. Profile variations of outer and inner diameters of molded specimens for various operational conditions were investigated. Sizes of outer and inner diameters of injection molded specimens were smaller than the sizes of mold. Part shrinkage decreased as outer diameter and thickness increased. Part shrinkage showed anisotropic behavior and it depended upon gate location. Subsequently, molded specimens were not circular but oval in shape, and showed the largest shrinkage in the direction of gate. It was realized that the mold design such as gate design is important to control the shape of molded products.

• Design & Manufacturing
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• v.12 no.2
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• pp.27-33
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• 2018

Korea's automobile industry, which has grown rapidly to become the world's fifth-largest automobile producer, To cope with environmental pollution and energy problems in order to prevail competitive edge in global market We are investing a lot of research personnel and costs. Among them, for realizing alternative light weight It is a part of the automobile module system that has achieved the technological development before the breakthrough in the injection molding process in the press process. Door module PNL was the subject of research. The door module PNL is expected to cause warpage before the mold production due to the thin and flat product characteristics and fiber orientation characteristic of the material. In this paper, CAE analysis and reverse correction tool Design. CAE analysis to obtain the results of weld line position, bending position and deformation value Through the correction tool, think3, the original product was modified before the mold production to improve the completeness of the parts. In fiber orientation, the position and size of the cooling channel in the mold, the position and size of the gate, Temperature, pressure, time, and work environment. Compared with the result of CAE analysis, the product that was reverse-corrected by Think3 was manufactured, and injection molding was performed. Injection molding products were tested 24 hours later. 3.5 mm to 7.0 mm, and under the fixed condition, the deviation was from 1.1 mm to 1.5 mm. Unlike the CAE analysis, the deviation of the actual injection pressure and the cooling temperature, the fiber orientation of the material, In order to solve this problem, it is necessary to compare the injection conditions with the database, I knew I had to catch the standard.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.489-494
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• 2004

Long Period Gratings (LPG) is currently receiving considerable attention because of their consistent measuring results fur pressure, temperature, strain and flow. LPG is easier to prepare and has a high sensitivity compared with Fiber Bragg Gratings (FBG). In addition, this kind of optical fiber sensors could be used for implementations in various structures. In this paper, LPG was used to monitor in situ the resin flow and the curing process in VARTM (Vacuum Assisted Resin Transfer. Molding). In order to demonstrate the effectiveness of the method, FBG is inserted into the glass mat to monitor the resin flow using optical spectrum analyzer (OSA). The curing reactions in VARTM are also observed using the same method. From the results, the attenuation wavelength shift and the loss change of attenuation band can be obtained from the status of the RTM (Resin Transfer Molding) sample owing to the internal variations of the .effective index, temperature, and pressure. It is shown that the proposed LPG is more effective in monitoring the curing reaction than FBG.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.375-382
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• 2010

In this study, we developed a method to predict the residual stress distribution and thermal deformation caused by in-mold labeling (IML) processes. IML is one of the injection molding processes for injecting a material into a cavity and subsequently inserting a decorated film. The IML process can yield products with decorations of outstanding excellent quality in only one working step. Although the IML process has various advantages, it causes defects such as film delamination, wash-out, and flow marks. In particular, deformation is considered to be a major concern in terms of delamination. To validate the model, the deformation predicted by using a numerical model was compared with experimental results, and both results showed good agreement. We verified that the developed method can be used to obtain the design guidelines for preventing delamination in the initial design stage of the IML process.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.18 no.2
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• pp.130-136
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• 2009

Semi-solid casting(SSC) of magnesium alloys is increasingly being used to produce high quality components. This process is similar to the injection molding of plastics and is called thixomolding. Using this process, higher strength, thinner wall sections and tighter tolerances without porosity are obtained. The high strength and low weight characteristics of magnesium alloys render the high-precision fabrication of thin-walled components with large surface areas. They are widely used for the IT, auto and consumer electronics industries. However, warpage of the thin-walled sections degrade quality of the parts produced in the SCC process. To produce thin-walled magnesium alloy parts, the geometry of gating system on the quality of the finished products should be clearly studied. In this paper, to minimize warpage of the thin-walled sections, Taguchi method is applied to the optimal design of the gate geometry in the thixomolding process. Width, height, length and angle of the gating system are selected for the robust design parameters. Effectiveness of the robust design is verified through the CAE software.

• Elastomers and Composites
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• v.47 no.4
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• pp.336-340
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• 2012

Residual stress in the injection molded part is originated from thermal shrinkage and shear stress during injection molding process. There are many measurement methods of residual stress in the plastic part. Residual stress in opaque products can be measured by chemical cracking test. This method enables the solvent and specimen to react and to cause cracks. Cracks developed according to the level of residual stress. Thus the stresses in plastic part can be quantitatively measured by counting the number of cracks or measuring the size of cracks. Relationship between stress and number of cracks in a plastic specimen has been investigated in this study. Bergen jig was used to give a strain in the specimens those were molded using PC/PBT and PC/ABS. Solvent for the chemical cracking test was prepared using tetrahydrofuran and methyl alcol with the ratio of 1 to 3. Stresses in the specimen can be calculated by strains those were imposed by Bergen jig. Cracks were developed for stress higher than certain level. The number of cracks increased by second order function for stress.