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Injection Gate Desin
Dec 26, 2017

Injction system is so importnat in the plastic mould design.
This will describe the sprue and runner system of molds. 


A sprue is a channel through which a molten plastic material is being injected from the nozzle of the injection machine into the mold. It has a smooth, round, tapered wall to allow smooth material flow.


Runner System


Runners are channels where material flows from the sprue to the cavities.

Conventional Runner

Improved Runner:

Balanced Runner: Resin is evenly distributed throughout the cavities. Volume and condition is the same. There is more material used because the total runner length is longer compared to the other two.

Hot Runner or sometimes called runnerless, can be more economical in high volume injection molding.

The narrow and shallow portion of the runner as it enters the cavity is called the gate.

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