The Pneumatic Shut-off Nozzle is an advanced injection molding component designed to provide precise control of molten plastic flow between the injection unit and the mold. By using compressed air to actuate the internal needle valve, the nozzle automatically opens during injection and closes immediately after the injection cycle, effectively preventing material leakage, stringing, drooling, and melt backflow.

Compared with conventional open nozzles, pneumatic shut-off nozzles significantly improve molding accuracy, reduce material waste, and enhance production efficiency. They are especially suitable for engineering plastics, high-temperature resins, low-viscosity materials, multi-cavity molds, hot runner systems, and automated production lines.

Manufactured from premium alloy steel and processed with precision CNC machining, our pneumatic shut-off nozzles deliver exceptional wear resistance, corrosion resistance, sealing performance, and long service life under demanding production environments.

Product Features

• Pneumatic automatic shut-off system
• Zero material leakage during machine idle time
• Accurate melt flow control
• Fast opening and closing response
• Excellent sealing performance
• High wear resistance
• High-temperature resistance
• Stable operation in continuous production
• Easy installation and maintenance
• Compatible with most injection molding machines
• Custom sizes and OEM solutions available

Working Principle

The pneumatic shut-off nozzle operates through compressed air supplied by the machine’s pneumatic control system.

Injection Stage

Compressed air drives the piston upward.

The internal needle valve opens.

Molten plastic flows smoothly into the mold cavity.

Holding Pressure

The valve remains open to maintain stable pressure and consistent melt flow.

End of Injection

The air pressure is released.

The return spring pushes the needle valve back to the closed position.

The nozzle seals automatically, preventing dripping or material leakage.

This automatic operation improves production stability while minimizing waste and cycle interruptions.

Main Components

The pneumatic shut-off nozzle consists of:

• Pneumatic Cylinder
• Piston Assembly
• Needle Valve
• Nozzle Tip
• Return Spring
• High Temperature Seals
• Air Inlet Port
• Precision Guide Sleeve
• Lock Nut
• Threaded Connection

Every component is manufactured with tight machining tolerances to ensure long-term reliability.

Technical Specifications

Material Options

Standard Alloy Steel

Suitable for general thermoplastics such as PP, PE and ABS.

SKD61 / H13 Tool Steel

Designed for high-temperature engineering plastics.

Bimetallic Version

Provides excellent wear resistance for glass fiber reinforced plastics and abrasive compounds.

Tungsten Carbide Coating

Ideal for extremely abrasive applications and long production cycles.

Advantages

Prevents Material Leakage

The automatic shut-off mechanism completely eliminates nozzle drooling during production.

Improves Product Quality

Consistent melt pressure reduces flash, short shots and dimensional variation.

Reduces Material Waste

No dripping means less resin loss and lower production costs.

Increases Productivity

Automatic opening and closing improve cycle stability and reduce operator intervention.

Long Service Life

Premium materials and advanced heat treatment ensure excellent durability under continuous production.

Excellent Compatibility

Suitable for most injection molding machines from global manufacturers.

Applications

Our pneumatic shut-off nozzles are widely used for producing:

• Automotive Components
• Medical Plastic Parts
• Electronic Connectors
• Household Products
• Food Packaging
• Cosmetic Packaging
• PET Preforms
• Thin-wall Containers
• Precision Engineering Parts
• Multi-cavity Molds
• Hot Runner Systems

Suitable materials include:

PP • PE • HDPE • ABS • PA • PC • PET • PMMA • POM • TPU • PVC • Glass Fiber Reinforced Plastics • Flame Retardant Materials • Engineering Plastics • Recycled Plastics