• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.39-40
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• 2008

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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• pp.275-278
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• 2007

In family mold, defects are frequently occurred by an excessive packing the smaller volume cavity during molding. Although runner size could be optimized by CAE analysis or experimental data, the filling imbalance is hardly avoided in the actual injection molding process by various means. Before this study, we developed a variable-runner system for balancing the cavity-filling for three resins (ABS, LDPE, and PA66) in the family-mold, and examined the effect of cross-sectional area reduction of a runner in the system. In this study, we examined the conditions of the pressure and temperature in the system with a CAE analysis. We also analyzed the influence of the rheological characteristic of resins to the balancing-capability of the system in order to help mold designers easily adopt the variable-runner system to their design.

• Elastomers and Composites
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• v.44 no.3
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• pp.232-243
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• 2009

The specialized and diversified synthetic and compounding technologies are used to meet the requirements for the advanced high performance tire tread materials with better balance of fuel economy(rolling resistance), safety(wet traction) and wear resistance. These techniques involve the methodology for the improvement of chemical and physical interaction between filler and the rubber matrix using coupling agents as well as a variety of chemically-modified solution SBRs. The research trends about the high performance functional SBRs and coupling agents which can interact with the surface of fillers and their working mechanism were investigated in the conventional carbon black-filled rubber and silica-filled SBR systems developed recently as "green tire".

• Design & Manufacturing
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• v.2 no.5
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• pp.25-29
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• 2008

Almost all injection molds have multi-cavity runner system for mass production, which are designed with geometrically balanced runner system in order to accomplish filling balance between cavity to cavity during processing. However, even though geometrically balanced runner is used, filling imbalance have been observed. Filling imbalance could be decreased by modifying processing conditions such as injections rate, mold temperature, injection pressure, melt temperature that are related to shear, viscosity. In this study, a series of experiment was conducted to investigate filling imbalance variation when modifying runner layout and ploymer and to determine which processing condition influences as the primary cause of filling imbalance in geometrically balanced runner system. The filling imbalance was desreased up to result range of $3{\leq}DFI{\leq}8(%)$ by using a new runner system for balanced filling.

• Design & Manufacturing
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• v.9 no.1
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• pp.23-26
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• 2015

For mass production of plastics, injection molds have multi-cavities. However, filling imbalance between cavity to cavity always has occurred in multi-cavities mold, and this has caused low quality of plastics part. In this study, the closed-loop-control system which can control temperature of hot manifold and nozzle in hot runner mold for filling balance has been suggested, and a series of experiment about difference of filling time and weight in cavity-to-cavity was conducted. As a result of using closed-loop-control system, a remarkable improvement in reducing filling imbalance was confirmed.

• Design & Manufacturing
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• v.2 no.6
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• pp.33-37
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• 2008

Almost all injection molds have multi-cavity, which are designed with geometrically balanced runner system in order to made filling balance between cavity to cavity during injection molding. However, filling imbalance has been existed in the geometrically balanced runner system. In this study, we made an experiment and investigated that are filling balanced according to material. Also, in case of filling imbalance was occurred, we conducted experiments in order to find out difference of cavity pressure with cavity pressure sensor. When filling imbalance was occurred between cavity to cavity, we investigated the filling imbalance and pressure differences by computer-aided engineering(CAE).

• Design & Manufacturing
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• v.6 no.1
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• pp.52-57
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• 2012

Aspect of filling imbalance that is originated from imbalanced share rate in runner is changed by material property, runner layout that are factors of changing viscosity and by injection pressure, injection speed, melt temperature and mold temperature that are injection conditions. In this paper, we made a study of runner system that is one of factor of filling imbalance and Sharp Conner Effect and Groove Corner Effect that are recently released. The study are showed that filling rate of between inside and outside cavity was influenced on shape of runner. Also, we suggested runner system for filling imbalance by adapting the two effects at multi cavity of unary branch type and theoretical investigated flow in the Shrap Conner runner type.

• Design & Manufacturing
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• v.8 no.2
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• pp.50-55
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• 2014

Recently, semi-stack mold have been developed for satisfying the various elements required in the mold industry. The mold is possible using with general-purpose injection molding machine by weight reduction through the improvement of the mold structure. In order to do that, tension core, spiral cooling system and half runner system were applied. It is effective for increased productivity and decreased of loss to the materials. However, the mold is required the filling balance in order to improve the quality and efficiency. Thus this study performed that optimum design and analysis of semi-stack mold for filling balance.

• Design & Manufacturing
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• v.7 no.1
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• pp.19-22
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• 2013

Almost all injection molds have multi-cavity runner system for mass production, which are designed with geometrically balanced runner system in order to accomplish filling balance between cavity to cavity during processing. However, even though geometrically balanced runner is used, filling imbalances have been observed. So, many studies for improving filling balance in the multi-cavities molds are worked up. In this study, the Melt-Buffer which is a new runner system for filling balance has been suggested, and a series of experiment about degree of filling balance in cavity-to-cavity was conducted in the mold with the Melt-Buffer. From the experiment, the filling balance was increased up to 5~6% by using the Melt-Buffer.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.47-56
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• 2006

It is well known that the family-mold has an advantage to reduce the cost for production and mold. However, defects are frequently occurred by over packing the smaller volume cavity during molding, especially when the family-mold has a volumetric difference between two cavities. In this study, the cavity-filling imbalance was confirmed by the temperature and the pressure sensors, and a variable-runner system was developed for balancing the cavity-filling. Experiments of balancing the cavity filling was carried out in the family-mold with the variable-runner system, and balancing the cavity-filling was confirmed by changing the cross-sectional area of a runner in the variable-runner system with the temperature and pressure sensors. The influence of the injection speed to the balancing-capability of the variable-runner system was also examined in the experiment.