三元乙丙橡胶注压成型工艺探究

Exploration of Injection Molding Process for EPDM Rubber

摘要

在固体火箭发动机中，绝热层、包覆套所采用的材料大多为三元乙丙橡胶，目前，三元乙丙橡胶的成型方式主要以模压工艺为主，涉及的模具有上下模、哈夫模，而采用哈夫模成型的部分产品，合模缝部位强度偏低，易出现开裂现象。此外，部分橡胶产品中含有金属嵌件，传统模压工艺对于嵌件定位难度大，装料困难。通过分析，哈夫模模压成型后的产品合模缝易开裂问题，主要原因为合模时的局部泄压造成；嵌件定位难度大，装料困难，主要是因为模压工艺中，料腔与型腔空间共用造成。而注压工艺中，注胶时，模具型腔始终处于锁紧状态，不存在泄压风险，且料腔与型腔分开，可有效解决嵌件定位问题以及装料问题。为此，有必要开展三元乙丙橡胶注压成型工艺探究。

Abstract

In solid rocket engines, the insulation layer and cladding are mostly made of ethylene propylene diene monomer (EPDM) rubber. Currently, the molding process of EPDM rubber is mainly based on compression molding, involving molds such as upper and lower molds and Haff molds. Some products formed by Haff molds have lower strength at the joint of the mold and are prone to cracking. In addition, some rubber products contain metal inserts, and traditional molding processes make it difficult to locate and load the inserts. Through analysis, it is found that the cracking problem of the mold joint in the product formed by Haf mold pressing is mainly caused by local pressure relief during mold closing; The difficulty in locating inserts and loading materials is mainly due to the shared space between the material cavity and the mold cavity in the molding process. In the injection molding process, when injecting glue, the mold cavity is always in a locked state, there is no risk of pressure relief, and the material cavity is separated from the mold cavity, which can effectively solve the problems of insert positioning and loading. Therefore, it is necessary to explore the injection molding process of EPDM rubber.

关键词

三元乙丙橡胶 / 注压成型 / 工艺探究

Key words

Ethylene Propylene Diene Monomer Rubber / Injection Molding / Process Investigation

参考文献

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