2.2 Limit the gate.
The cavity and the runner are connected by a channel with a short distance at one end and a small section. This channel is called a restrictive gate, which limits the thickness of the gate and rapid solidification. The main types of restriction gates are:

2.2.1 Point gate.

Point gate is a round gate with extremely small cross-sectional size. The characteristics of the point gate are: 1. The gate position is limited; 2. After the gate is removed, the residual trace is small and does not affect the appearance of the plastic part; 3. The gate can be automatically broken when the mold is opened, which is conducive to automatic operation; 4. The stress caused by the filling of the gate attachment is small. The disadvantages are: 1. The pressure loss is large. The mold must adopt a three-plate mold structure. The mold structure is complicated, and it must have a sequential mold splitting mechanism. It can also be applied to a two-plate mold structure without runners.

2.2.2 submarine gate;

The latent gate is evolved from the point gate. Its runner is opened on the parting surface. The gate sneaks under the parting surface and enters the cavity along an oblique direction. The latent gate has the characteristics of a point gate. , The inlet gate is generally on the inner surface or hidden side of the plastic part, so it does not affect the appearance of the plastic part. The plastic part and the runner are equipped with an ejection mechanism. When the mold is opened, the gate is automatically cut off and the runner condenses Automatically fall off.