• Title/Summary/Keyword: 다수 캐비티 금형

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The Filling Imbalance in Multi-Cavity Injection Molds with Unary Branch Type Runner Lay-out (편측 분기형 러너 배열을 가진 다수 캐비티 사출금형에서의 충전 불균형도)

  • 강철민;정영득
    • Transactions of Materials Processing
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    • v.13 no.7
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    • pp.580-585
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    • 2004
  • Almost all injection molds have multi-cavity runner system fur productivity and are designed with geometrically balanced runner system in order to minimize filling imbalance between cavity to cavity during processing. However, filling imbalances have been observed though geometrically balanced runner lay-out. Generally, these filling imbalances are due to thermal unbalance, viscosity, characteristic of polymers and so on. These kinds of filling imbalances have already been reported by Beaumont since 1997, but his research has mainly focused on filling imbalance at binary runner. In this study, we conducted an experimental study about the filling imbalances in unary branch runner as well as binary branch runner and inquired into the causes of filling imbalances. The results could be summarized as fellowing: Filling imbalances existed in multi-cavity mold with unary branch runner, it could be decreased by optimizing processing condition such as increasing injection rate, and it is almost proportion to each polymer's temperature sensibility.

The Effects of Runner Core Pin on the Filling Imbalance Occurred in Multi Cavity Injection Mold (다수 캐비티 사출금형에서 러너 코어핀이 충전불균형에 미치는 영향)

  • Kang C. M.;Jeong Y. D.;Han K. T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.05a
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    • pp.39-42
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    • 2005
  • For mass production, usually injection mold has multi-cavity which is filled through geometrical balanced runner system. Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed. These filling imbalances are one of the most significant factors to affect quality of plastic parts when molding plastic parts in multi-cavity injection mold. Filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during injection molding processing. This paper presents a solution of these filling imbalances through using 'runner core pin'. The runner core pin which is developed in this study creates a symmetrical shear distribution within runner. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed.

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Runner Design for Filling Balance in Multi-cavity Injection Mold (다수 캐비티 사출금형에서 충전 균형을 위한 런너의 설계)

  • Kang, M.A.;Lyu, M.Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.05a
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    • pp.329-332
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    • 2008
  • Flow imbalance among the cavities was often observed in multi-cavity mold. The flow imbalance affects on the dimensions and physical properties of melded articles. First of all, the origin of flow imbalance is geometrical imbalance of delivery system. However, even the geometry of delivery system is balanced the cavity imbalance is being developed. This comes from the temperature distribution in the cross-section of runner, which is affected by the operational conditions. In this study, experimental study of flow imbalance has been conducted for various injection speeds. This study also suggests new runner design to eliminate flow imbalance in multi-cavity injection mold. Simulation and experimental results showed suggested new designed runner could eliminate or reduce flow imbalance in multi-cavity injection mold.

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Development of Runner System for Filling Balance in Multi Cavity Injection Mold (다수 캐비티 사출금형에서 균형 충전용 러너 시스템 개발)

  • Jeong Y. D.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2005.09a
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    • pp.13-16
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    • 2005
  • For mass production, usually injection mold has multi-cavity which is filled through geometrical balanced runner system. Despite geometrical balanced runner system, filling imbalances between cavity to cavity have always been observed. These filing imbalances are one of the most significant factors to affect quality of plastic parts when molding plastic parts in multi-cavity injection mold. Filling imbalances are results from non-symmetrical shear rate distribution within melt as it flows through the runner system. It has been possible to decrease filling imbalance by optimizing processing conditions, but it has not completely eliminated this phenomenon during injection molding processing. This paper presents a solution of these filling imbalances through using 'runner core pin'. The runner core pin which is developed in this study creates a symmetrical shear distribution within runner. As a result of using runner core pin, a remarkable improvement in reducing filling imbalance was confirmed.

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A Study on mold manufacture of multi-cavity dental iodine container using powder injection molding (분말사출성형을 이용한 다수 캐비티 치과용 요오드 용기 금형제작에 관한 연구)

  • Choi, Jae-Hoon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.1
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    • pp.21-26
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    • 2014
  • When iodine container for dental mouth treatment is opened, thread for treatment is cut by the blade in cap of container. Due to the problem of corrosion in a short period time after the reaction of metal blade to iodine solution, it gives impact on patient hygiene. In order to solve the problem, alternative products such as ceramic blade are developed and produced recently. In case of ceramic blade, it is produced by handwork and machine work. In this study, for the quantity production of ceramic blade with powder injection molding, we proposed a delivery system to have uniform charge of 20 cavity. Using Moldflow, simulation on 20 Cavity flow was performed. And then the mold was obtained through mold production and modification.(based on simulation) After injection molding, debinder, sintering process was achieved for ceramic blade, and the cap product was completed via insert injection on ceramic blade. In this study, we verified possibility of quantity production of ceramic blade which showed effective performance for cutting.

Investigation of Molding Characteristics in Injection Compression Molding According to Molding Conditions through Birefringence (사출압축성형에서 복굴절을 통한 성형조건에 따른 성형특성 고찰)

  • Lee, Dan Bi;Nam, Yun Hyo;Lyu, Min-Young
    • Polymer(Korea)
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    • v.38 no.2
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    • pp.193-198
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    • 2014
  • Lens and DVD require high quality of optical property. Conventional injection molded products contain high residual stress and this invokes birefringence since high cavity pressure and high temperature variation are involved in a molding process. Thus these products are often molded by injection compression molding in order to minimize the residual stress through reducing cavity pressure and uniform cavity pressure. In this study, molding parameters affecting molding quality such as property uniformity in injection compression molding were investigated through experiment. Molding quality deviations among the cavities in multi-cavity mold were also studied. Transparent resins, PC and PS were used in this study. Compression gap, compression speed, compression force, and compression delay time for processing variables in injection compression molding were applied in experiment. Compression force, compression delay time, and compression gap significantly affected the optical property of product. The degree of influence of process variable on the product quality was different in different resins. This implies that the optimal operational conditions in injection compression molding existed for each resin according to flow property.