Hydraulic Core-pull Precision Injection Mold

Hydraulic core-pull precision injection mold incorporates hydraulic cylinders to actuate side cores, producing plastic parts with undercuts, side holes, or internal threads. The 3D view shows the mold with side hydraulic cylinders and cooling lines.

Core Pull Mechanism

When a part has undercuts or side features that would prevent ejection from a straight mold, a side core is used. The core is withdrawn hydraulically before the ejector pins activate. Hydraulic core pulling is preferred for large undercuts or heavy side forces, where angled pins would be insufficient.

Components

• Hydraulic cylinders mounted on the mold sides.

• Side core slides guided by wear plates.

• Limit switches to confirm core position.

• Cooling lines through slides and core inserts.

• Precision guide pillars for mold alignment.

Applications

Core-pull molds produce threaded caps, pipe fittings, connectors, and parts with side holes or snap-fit features. Hydraulic actuation is used for deep undercuts, large cores, or parts where multiple side actions must be synchronized.

Process Sequence

After injection and cooling, the mold opens slightly. The hydraulic cylinders pull the side cores out of the undercuts. Only then do the ejector pins push the part off the core. On mold closing, the cylinders push the cores back before the injection cycle begins.

Conclusion

The hydraulic core-pull precision injection mold enables complex undercut parts that cannot be molded with a simple two-plate design. Hydraulic actuation provides the force and precision needed for production-quality side features.