2.1 Unrestricted gate.
Unrestricted gate is also called straight gate. Its characteristic is that the plastic melt flows directly into the cavity, the pressure loss is small, the feeding speed is fast and the molding is easier, and it is suitable for all kinds of plastics. It has the advantages of good transmission pressure, strong pressure maintaining and shrinking effect, simple and compact mold structure, and convenient manufacturing. However, it is difficult to remove the gate, and the marks of the gate are obvious; the heat concentration near the gate and the slow condensation are prone to large internal stress, and it is also prone to shrink pits or surface shrinkage. Suitable for large plastic parts, thick-walled plastic parts, etc.