• Elastomers and Composites
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• v.55 no.2
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• pp.120-127
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• 2020

In this study, molding shrinkage of PPS resin was investigated. Two types of PPS resins with differing glass fiber and calcium carbonate content were used for this purpose. To observe mold shrinkage, molding conditions based on injection temperature, injection speed, and the position of the cushion were selected. Circular and rectangular specimens were used for the study model. Injection molding simulation was performed to predict the filling pattern and mold shrinkage, and the simulation results were compared with the experimental conclusions. It was observed that the mold shrinkage showed the highest shrinkage (distributed from 0.05% to 0.32%) dependence on the injection temperature, and the lowest shrinkage (distributed from 0.05% to 0.31%) dependence on the injection speed. The role of the position of the cushion in mold shrinkage was difficult to observe. The results of the simulation mostly agreed with the experimental results; however, for some molding conditions, the mold shrinkage in the simulation was overestimated as compared to that in the experiment.

• Elastomers and Composites
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• v.57 no.4
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• pp.138-146
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• 2022

Research on the reduction of plastic use to prevent environmental pollution is urgently needed. Accordingly, studies on reducing the weight of polyethylene terephthalate (PET) bottles are currently being conducted. PET bottles are fabricated by injection stretch blow molding. In this study, stretch blow molding for fabricating PET bottles using preform studied through a computer simulation. Blowing characteristics are analyzed by varying the start time of the pre-blow, which is one of the process conditions of stretch blow molding. Simulation results and the preform inflation process are presented, and the parameters of stretch ratio, stretching path, thickness distribution, and weight distribution of blown PET bottles are investigated.

• Elastomers and Composites
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• v.56 no.3
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• pp.164-171
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• 2021

Due to the problem of environmental pollution by plastics, it is necessary to decrease their consumption. In the case of PET bottles, it is essential to reduce the thickness of the bottle for the reduction of plastic used. For manufacturing PET bottles with reduced thickness, it is a prerequisite to design a preform with reduced thickness and study its molding capability. In this study, the injection molding capability was investigated after reducing the body thickness of the preform to 15% and 20%, respectively, for the two preform models currently in use. Injection molding analysis was performed on the existing models and on the models for reduced weight, under the molding conditions of the existing models. Using the computed results, temperature distribution, pressure distribution, deformation and clamping force were compared. Based on the analysis, the injection conditions of the preform model with less thickness were discussed.

• Journal of the Korean Society of Industry Convergence
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• v.10 no.2
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• pp.123-128
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• 2007

The demand for the precision rubber products has been rapidly increasing with the recent growth of industries. And the requirement for the productivity and the quality calls out for the injection molding machines with the precision machining ability as well as the high productivity. Especially modern automobile industry is in urgent need of developing injection molding machines for the high quality rubber products with high productivity. And the inability of the domestic companies to meet the standards causes importing foreign machines and as a result spending good amount of dollars. It is extremely important to develop competitive machines and strengthen the infrastructure of the related industries. In this paper the functions and the structure of a automatic multi-nozzle injection molding machine has been studied to set up a proper test system for the precision rate and the reliability of the machines, which can help build the machines to meet the request of the industry.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.577-578
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• 2006

In this paper, the rubber behavior was calculated for obtaining the optimal process condition which is for producing a transformer with a given performance. This study was carried out using the computer simulation of injection mold filling and packing simulations. In order to remove the crack of product, proper locations of the runner and cooling system configurations could be determined. Based on these results, the transformer is developed by injection molding and guidelines of part design, mold design and processing conditions are established. Finally, the cast savings, cycle time reduce and improvement of productivity will be obtained.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.179-182
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• 2007

In recent, recycling of plastic material has became a major issue due to the landfills and environmental problem. This study investigated fluidity of thermoplastic vulcanizate(TPV), which is for automobile component parts such as weather strip in order to replace ethylene propylene rubber (EPDM). So, using the spiral flow test mold and panel cover mold, we conducted an experiment on fluidity of TPV with injection molding. As results of injection molding experiment, the recycled TPV's flow length was a little bit longer than virgin TPV and a case of panel cover, the filled weight was almost same quantity.

• Design & Manufacturing
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• v.1 no.1
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• pp.39-44
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• 2007

In recent, recycling of plastic material has became a major issue due to the landfills and environmental problem. This study investigated fluidity and hardness of thermoplastic vulcanizate(TPV), which is used for automobile component parts such as weather strip in order to replace ethylene propylene rubber (EPDM). So, using the spiral flow test mold, we conducted an experiment on fluidity and hardness of TPV according to injection molding conditions. As results of injection molding experiment, the recycled TPV's flow length was a little bit longer than virgin TPV and the hardness was decreased in case of using the recycled resin. Also, we investigated the morphology study by SEM photo.

• Transactions of Materials Processing
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• v.16 no.4 s.94
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• pp.271-275
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• 2007

These days, recycling of plastic material has become a major issue due to the landfills and environmental problem. This study investigates the fluidity of thermoplastic vulcanizate(TPV), which can be used for an automobile part such as a weather strip, in order to replace ethylene propylene rubber(EPDM). Injection molding experiments with the spiral flow test mold and panel cover mold are conducted to examine the fluidity of TPV during injection molding. It is found out that the recycled TPV's flow length is a little bit longer than the virgin TPV. However, the filling weight for a panel cover parts by a recycled TPV is almost the same as that by a virgin TPV.

• Elastomers and Composites
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• v.39 no.4
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• pp.324-329
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• 2004

The phase morphology, degree of craze and impact property in Polycarbonate (PC)/Acrylonitrile-Butadiene- styrene (ABS) blend containing the phosphate based flame retardant were studied in terms of injection molding temperatures. As the injection molding temperature increases, significant amount of coalescences and crazes were observed and impact strength decreased. It was also observed that the addition of compatibilizer into the blends suppresses the coalescence and craze.

• Transactions of Materials Processing
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• v.24 no.6
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• pp.418-425
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• 2015

Based on eco-friendly advantages and the enhanced development in the chemical and physical characteristics, liquid silicone rubber (LSR) is widely used in producing precision parts in the automotive, medical, electronics, aeronautical and many other industries. In the current work, a thermoplastic-thermoset multi component injection molding (MCM) was developed for a waterproof automotive connector housing using PBT and LSR resins. Measurements of the rheological characteristics of PBT and LSR were made to improve the reliability of the numerical analysis for the multi component injection process. With the measured viscosity, pvT and curing data, numerical analysis of the multi cycle injection molding was conducted using simulation software (Sigma V5.0).