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:
<ul>
<li>Glass-filled nylons → Tungsten carbide coated full-ring</li>
<li>Clear PC (optical grade) → Sliding ring with polished finish</li>
<li>PVC rigid → Mazel-type, chrome-plated</li>
<li>General purpose → Standard full-ring nitrided</li>
</ul>

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.

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还有什么补充参数吗？一起完善。