多级注射成型工艺在PVC-U管件生产中的应用

通过对多级注射成型工艺特点的分析，给出多级注射工艺的特性曲线；结合多级注射成型工艺在硬聚氯乙烯（PVC－U）管件加工中的应用，总结出PVC－U管件加工中多级注射工艺流程特性曲线的特点，举例说明了多级注射成型工艺的使用方法，提出了PVC－U管件生产中不易解决的注射缺陷，如注射银纹，烧伤，熔接痕及排气等问题有效解决方法。

APPLICATION OF MULTI-STAGE INJECTION MOULDING IN THE PRODUCTION OF PVC-U PIPING

Through the analysis of the multi-stage injection moulding, the characteristic curve of the process with multi-stage injection is given. Integrated with its application in process of PVC-U piping fabrication, the conclusion is made with the features and the flow chart of the process with multi-stage injection for PVC-U piping fabrication. The way of how the multi-stage injection works is illustrated with some examples. Some methods are given regarding removing the defects such as injection craze, burning, some welding lines and air vent problems.