Double injection molding, also called 2K molding, two shot molding
Due to the appearance, decoration or the function requirements, such as “partial ABS area electroplating”, some product should be designed using two or three different colors or materials to do injection molding, mostly is two. One very common example in our daily life is the toothbrush. It is designed to be soft combined with hard plastic. The purpose on the one hand is to make it strong enough, on the other hand is to make the user feel comfortable.
Two shot mold consists of two same cores (A1, A2) and two different cavities (B1, B2). A1 is completely same as A2 (A1=A2), thus with a strict accuracy requirements.
The runner system of the two molds is different and they work at the same time. Every cycle has two times injections.
After the first shot, gate will be ejected automatically and core A1 rotates to the position of core A2 by 180°to start the second injection.