• 폴리머
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• 제33권6호
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• pp.561-568
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• 2009

소형 플라스틱 부품들은 대부분 다수 캐비티 빼기 사출금형에서 성형된다. 이러한 다수 빼기 캐비티 금형에서의 사출성형은 캐비티간의 흐름 균형이 중요하다. 캐비티간 흐름의 불균형은 성형품의 캐비티간 물성 및 품질의 편차를 초래한다. 캐비티간의 흐름균형은 런너와 게이트에서의 흐름균형을 통하여 이루어지게 되는데 런너와 게이트에서 기하학적인 균형을 이루어도 열적 불균형으로 캐비티간 흐름의 불균형을 초래한다. 본 연구에서는 캐비티간 흐름의 균형을 위해 고안한 스크류 타입의 런너을 이용하여 캐비티간 충전균형을 고찰하였다. 여러 형태의 스크류 런너에서 결정성 수지와 비결정성 수지, 그리고 점도가 높은 수지와 점도가 낮은 수지를 이용하여 캐비티간 흐름을 관찰하였다. 흐름의 균형은 성형조건 중 사출속도에 따라 다르게 나타나기 때문에 사출속도를 변화해 가며 관찰하였다. 실험 결과를 성형해석과 비교 검토하였으며 서로 잘 일치함을 확인할 수 있었다. 스크류 런너에서 수지가 흐르면서 스크류 채널을 따라 회전운동을 하여 스크류 단면에서 온도가 균일하게 됨을 확인하였다. 그리구 이러한 균일한 온도 때문에 캐비티간 흐름 균형이 이루어지고 있음을 확인하였다. 결론적으로 실험에 사용된 새롭게 고안된 스크류 타입의 런너는 캐비티간 충전균형을 이루는데 매우 효과적임을 실험과 해석을 통해 검증할 수 있었다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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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.

• 한국금형공학회:학술대회논문집
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• 한국금형공학회 2008년도 하계 학술대회
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• pp.155-158
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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 molded 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.

• 소성∙가공
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• 제16권1호
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• pp.54-60
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• 2007

Optimum injection molding condition for a box mold was searched by the Response Surface Analysis(RSA) with the aid of process monitoring system(PMS). Process variables on the control panel of the injection molding machine such as barrel temperatures, screw speed profile, holding pressures, etc. cannot guarantee the uniformity of the material variables directly related with the state of the product in the mold cavity. In order to make sure the state of the resin in the cavity, pressures and temperatures in the cavity, runner and nozzle were monitored in the experiment with the PMS. To accomplish the consistency of the molding process, dependent variables such as the switchover point and holding time were searched with the PMS. With a proper objective function about deflection of the box-type product, the optimum injection molding condition was obtained.