Views: 0 Author: Site Editor Publish Time: 2025-04-09 Origin: Site
Rotating thread molds operate through a mechanical or hydraulic rotation system that twists the threaded core out of the molded part.
Mold Clamping & Injection
Plastic (PP, PE, or PET) is injected into the cavity.
Cooling & Thread Formation
The threaded core holds the plastic in place as it solidifies.
Ejection & Unscrewing
After cooling, the mold opens, and the threaded core rotates (clockwise or counterclockwise) to release the cap.
Part Ejection
The cap is ejected, and the core resets for the next cycle.
Cycle Time: Typically 3-8 seconds for high-speed production.
| Component | Function | Material/Technology |
|---|---|---|
| Rotating Core | Forms threads | Hardened steel (HRC 52-56), often coated with TiN for wear resistance |
| Drive Mechanism | Powers rotation | Hydraulic motor / Servo motor (more precise) |
| Gear System | Transmits motion | Helical gears (for smooth torque transfer) |
| Guide Bushings | Ensures alignment | Bronze or self-lubricating polymer |
| Counting Sensor | Controls rotation | Encoder (ensures exact turns per cycle) |
| Feature | Rotating Thread Mold | Slide-Action Mold |
|---|---|---|
| Thread Quality | No parting lines, smooth finish | Visible parting lines |
| Production Speed | Faster (3-8 sec/cycle) | Slower (8-15 sec/cycle) |
| Tooling Life | Longer (1M+ cycles) | Shorter (500K cycles) |
| Complex Threads | Handles multi-start, fine, or reverse threads | Limited to simple threads |
| Maintenance | Higher initial cost, but lower long-term wear | Frequent slide wear |
✅ Best for: High-volume production (e.g., beverage caps, medical bottles).
❌ Not ideal for: Low-volume orders (due to higher mold cost).
Beverage Bottle Caps (PCO 1881, 28mm standard)
Pharmaceutical Closures (Child-resistant, tamper-evident)
Cosmetic Jar Lids (Fine threads for premium feel)
Automotive Fluid Caps (Oil, coolant containers)
Rotating Thread Mold Pitch & Direction (Right-hand vs. left-hand)
Core Rotation Speed (Too fast = thread stripping)
Cooling Channels (Prevent warping in thick sections)
Ejection Force (Avoid cap deformation)
Electric Servo-Driven Cores (More precise than hydraulic)
Quick-Change Systems (Swap cores in <15 mins for different threads)
Smart Sensors (Real-time torque monitoring to prevent defects)
Rotating thread molds are the gold standard for high-precision, high-speed cap production. While they require higher initial investment, their superior thread quality, durability, and efficiency make them indispensable for mass production.
