The automatic unscrewing injection mold integrates a mechanical or hydraulic rotary mechanism to eject threaded parts directly from the mold without manual intervention. Ideal for high-efficiency mass production of caps, valves, connector housings, and other threaded-plastic components.
Overview
An Automatic Unscrewing Injection Mold features built-in rotating or linear actuators that unscrew threaded plastic parts from the core immediately after molding. This specialized tooling streamlines the demolding of internal and external threads in a fully automated cycle.
Operating Principle
• Threaded Core Design: Screw-threaded cores are installed into the mold’s moving half; these cores can rotate or translate axially while the mold remains clamped.
• Drive Mechanism: Gears, cams, hydraulic or pneumatic cylinders impart controlled rotation and/or linear motion to the cores.
• Demolding Sequence:
After melt-holding, ejector pins pre-push parts slightly off the cores.
The unscrewing mechanism actuates, rotating the core relative to the part to “unscrew” it.
Final ejection completes the cycle and the mold closes for the next shot.
Key Components & Functions
• Turntable Unscrewing: Integrated rotary plate with multiple thread cores for multi-cavity molds.
• Linear Unscrewing: Combined rotary-then-axial actuation via hydraulic/pneumatic cylinders—compact footprint.
• Synchronization & Control: Linked to the press’s PLC or a dedicated controller for full automation.
• Safety Interlocks: Prevent mold opening or over-rotation during the unscrewing cycle.
Core Advantages
• High Efficiency: Eliminates manual screw-off steps, cutting cycle time by 15–30%.
• Consistent Quality: Adjustable torque and rotation angle ensure uniform thread integrity.
• Cost Reduction: Less manual labor, lower scrap rates, and minimal secondary operations.
• Design Flexibility: Compatible with hot-runner systems, multi-shot molding, and multi-cavity layouts.
• Material Compatibility: PA, POM, PE, PP, PC/ABS and other engineering plastics.
Sample Specifications
• Cavities: 1–8 (customizable)
• Thread Diameter Range: Ø5–Ø50 mm (expandable)
• Rotation Angle: 360° or multi-turn settings
• Torque Capacity: 50–200 N·m
• Drive Types: Mechanical gear, hydraulic cylinder, pneumatic cylinder
• Control Modes: Synchronized to press / Standalone PLC / Touchscreen HMI
Typical Applications
• Packaging: Screw caps, spray nozzles, cosmetic closures
• Automotive: Oil filler caps, quick-connect fittings, hose connectors
• Household Appliances: Faucet handles, adjustable valve bodies
• Industrial: Pneumatic tube fittings, cable-tie fasteners, threaded mounting brackets
Selection & Maintenance
• Selection Tips: Choose core size, drive mechanism, and control strategy based on thread pitch, part dimensions, tolerance, and cycle requirements.
• Preventive Care: Regularly lubricate moving parts, inspect seals, and clean threads to maintain smooth operation.
• Troubleshooting: Address incomplete unscrewing or slippage by checking drive pressure, stroke settings, and thread matching between core and part.
