Screw Tip Types for Injection Molding: Which One to Choose
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When selecting screw tips for injection molding machines, the material being processed largely determines the optimal design.
Common screw tip types:
Full-Round Check Ring — Best for general-purpose materials like ABS, PP, PE. Provides reliable backflow prevention with moderate wear resistance.
Sliding Ring — Preferred for high-viscosity materials (PC, PMMA, PVC-U). The ring slides along the shaft rather than rotating, reducing wear on mating surfaces.
Ball Check Valve — Suitable for low-viscosity materials (PA, POM). Simple construction but can cause material holdup in the ball seat area.
Mazel-Type — Designed for heat-sensitive materials (PVC, PVDC). Streamlined flow path minimizes residence time.
Selection guide by material:
- Glass-filled nylons → Tungsten carbide coated full-ring
- Clear PC (optical grade) → Sliding ring with polished finish
- PVC rigid → Mazel-type, chrome-plated
- General purpose → Standard full-ring nitrided
Replace check rings when you see shot weight variation >3 percent or visible wear on sealing surfaces. Typical lifespan is 4000-8000 operating hours depending on material abrasiveness.
What type are you using on your injection press? Share your experience below.
还有什么补充参数吗？一起完善。