What is real overmold,mould design is important!
As last article,we introduced the main type overmold is the way to make soft part and hard part in one mould,usually we call it a real overmold,often named double injection mould,finished part will be formed in 2 steps automatically in the same machine. This kind mould is highly required for mould design,mould cost is often more than 2 times than the first type ,but it is cost efficient for high volume production, characteristics as below: 1) Mould structure should be designed according to part and injection machine paticularly. 2) Mould just work in double injection machine,it has 2 feed tubes ,either for hard plastic or soft plastic. 3) Mould core side have 2 same cavities,but the 2 cavities of mould cavity side is different, one for soft material other for hard.after hard part injected,mould core rotate 180 degree to close with mould cavity to proceed soft part injection.mould cavity keep fixed in working. 4) How to make the mould core and mould cavity closed exactly after rotating 180 degree is critical and difficult for the mould. 5) The cavity of hard part should be considerred normal shrinkage,but for soft part often dont apply shrinkage due to the relative location will be changed.