The concept of secondary ejection of plastic mold is: firstly, all ejector pins are ejected synchronously. After ejecting to the set position, some ejector pins stop ejecting, and the rest continue to eject until the ejection is completed.

Generally speaking, there are three kinds of secondary roof structures, which are adopted according to the actual situation.

The first one is to use the back tension spring to cooperate with the limiting column of the primary ejection plate to complete the secondary ejection;

Secondly, the elastic sleeve device is used to complete the secondary jacking;

The third is to use the three-layer sleeve shaft and clamping ball to float back and forth to complete the secondary jacking.

Space is limited, so I can't explain it in detail. I can only insert a picture. The first two structures are very common, so I don't want to draw them!

Schematic diagram of the third structure: