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Language: korean

Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

Publication history: Received April 21, 2010
Accepted May 12, 2010

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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방진고무사출성형의 적정설계

Optimum Design of Rubber Injection Molding Process for the Preparation of Anti-vibration Rubber

임광희^†

Kwang-Hee Lim^†

대구대학교 화학공학과, 712-714 경북 경산시 진량읍 내리리 15

Department of Chemical Engineering, Daegu University, 15 Naeriri, Jillyang-eup, Gyeongsan-si, Gyeongbuk 712-714, Korea

khlim@daegu.ac.kr

Korean Chemical Engineering Research, August 2010, 48(4), 490-498(9), NONE Epub 8 September 2010

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Abstract

K사의 방진고무 사출성형에 있어서 애로사항인 토크로드부시(torque rod bush)의 캐비티 가장자리 (edge) 구간에서의 에어트랩(air-trap) 발생 및 다이내믹 댐퍼(dynamic damper)에 있어서 사출시 미성형(short shot) 발생 등의 문제점을 해결하기 위하여, 상용 CAE 프로그램인 MOLDFLOW(Ver. 5.2)를 이용한 전산모사를 수행하여 적정금형설계를 도출하고 적정작업조건을 구축하였다. 그 결과 방진고무 중에서 토크로드부시의 사출성형에서의 에어트랩 발생 등의 공정문제를 최적 캐비티 가장자리 경사각 및 게이트 수를 조절함으로써 캐비티 가장자리에서의 유동선단(flow-front)의 유동정체를 방지하고 유동을 원활하게 하여 해결하였다. 한편 다이내믹 댐퍼의 사출시 충전(filling) 단계에서의 캐비티 비충전으로 인한 미성형 불량은 에어벤트(air-vent) 구를 에어트랩 발생 빈도가 매우 높은 유동선단 상향류와 하향류의 두 흐름이 만나는 지점에 설치함으로써 미성형 불량을 해결하였다. 또한 게이트 위치를 댐퍼 상단에서 중단으로 변경하거나 게이트 수를 증가시킨 경우에 미성형 불량이 K사의 경우보다 개선되었다.

The optimum mold design and the optimum process condition were constructed upon executing process simulation of rubber injection molding with the commercial CAE program of MOLDFLOW(Ver. 5.2) in order to solve the process-problems of K company relating to air-traps and short-shots. The former occurs at the cavity edge of torquerod-bush and the latter takes place for the injection molding of dynamic dampers. As a result the process problem relating to air traps was solved by optimizing edge-angle and the number of gates to prevent the flow congestion of flowfront and to make the flow-front movement unaffected by congestion. For dynamic dampers of K company the unmolded flaw caused by their unfilled cavity was corrected by installing the air-vent at the confronting locations of both upstream and downstream of flow-front where air traps frequently occur. Besides the unmolded flaws were rectified by altering the position of gate from the upper to the middle or by increasing the number of gates. Thus the process problems of K company relating to air-traps and short-shots of torque-rod-bush and dynamic dampers, respectively, were solved by proper altering of mold design with process simulation of rubber injection molding.

Keywords

Rubber Injection Molding Process Simulation Optimum Process Condition Air Trap Short-Shot

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