Permeable Steel and Its Application in Plastic-injection Mould  

作　　者：ZHOU Zhaoyao CAO Wenjiong WU Zhengqiang YU Minqiang LI Yuanyuan 

机构地区：[1]School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China

出　　处：《Chinese Journal of Mechanical Engineering》2010年第3期312-316,共5页中国机械工程学报（英文版）

基　　金：supported by Guangdong-Hong Kong Key Project of China (Grant No. 2007Z010);National Basic Research Program of China (973 Program, Grant No. 2007CB616905)

摘　　要：The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the dependence on the venting system complicates the mould design. Furthermore in certain condition, it is difficult to integrate the venting system into the mould. Currently a kind of mold material which has gas permeability has been developed in abroad, but the applications of this mold material were restricted by its higher cost and smaller size. In this research, a porous material which was made by powder metallurgy was applied to plastic mould to replace the venting system. Permeability of the steel with different secondary processing was tested and compared with a special apparatus. The metallographic samples of the steel with different secondary processing were prepared and investigated. Finally an actual injection set was established to investigate the applications of permeable steel. The metallographies indicate that the micro-holes inside permeable steel were interconnected. Moulds made of permeable steel exhibit good permeability in the plastic-injection experiments and gas generated in the mould cavity was smoothly exhausted. The melted plastic did not penetrate into the mould or block in the micro-holes. After several times of plastic-injection experiments, the mould still retained good permeability. The strength of this permeable steel is between 200–250 MPa and suitable for industrial applications. The venting systems simplified by permeable steel in plastic-injection have simple structures, which can be applied into any place that requires gas exhausting.The gas in plastics mould has great influence on performance, appearance and lifespan of the injection molded parts. Venting channel and its appendix system should be used for gas exhausting in general. However, the dependence on the venting system complicates the mould design. Furthermore in certain condition, it is difficult to integrate the venting system into the mould. Currently a kind of mold material which has gas permeability has been developed in abroad, but the applications of this mold material were restricted by its higher cost and smaller size. In this research, a porous material which was made by powder metallurgy was applied to plastic mould to replace the venting system. Permeability of the steel with different secondary processing was tested and compared with a special apparatus. The metallographic samples of the steel with different secondary processing were prepared and investigated. Finally an actual injection set was established to investigate the applications of permeable steel. The metallographies indicate that the micro-holes inside permeable steel were interconnected. Moulds made of permeable steel exhibit good permeability in the plastic-injection experiments and gas generated in the mould cavity was smoothly exhausted. The melted plastic did not penetrate into the mould or block in the micro-holes. After several times of plastic-injection experiments, the mould still retained good permeability. The strength of this permeable steel is between 200–250 MPa and suitable for industrial applications. The venting systems simplified by permeable steel in plastic-injection have simple structures, which can be applied into any place that requires gas exhausting.

关 键 词：powder metallurgy permeable steel plastic-injection mould venting system 

分 类 号：TQ320.52[化学工程—合成树脂塑料工业] X928[环境科学与工程—安全科学]