Straight Core Sleeves
Tubular steel sleeves for precision guided alignment. Protect both pin shaft and plate bore from wear.
Products in This Category
JIS Standard M2 Steel Straight Core Pins - Core Pin | OEM Available
Straight Core Pins in M2 Steel with Core Pin. Engineered for plastic injection molding with custom options. Contact us.
JIS Standard M2 Steel Straight Core Pins - Core Pin | OEM Available
Straight Core Pins in M2 Steel with Core Pin. Engineered for plastic injection molding with custom options. Contact us.
How to Specify Core Sleeves
Core sleeves must match both the core pin shaft and the mold plate bore. Three dimensions are critical:
| Variant | Description | Best For | Recommendation |
|---|---|---|---|
| Inner Diameter (ID) | Must match the core pin shaft OD with clearance fit for guided sliding | Pin guidance and lateral constraint during injection | H7 tolerance (sliding fit) |
| Outer Diameter (OD) | Must match the mold plate bore ID with interference fit for retention | Sleeve retention in plate, bore protection | k6 tolerance (press fit) |
| Overall Length | Equal to plate thickness at the installation point | Full-length support for the core pin shaft | ±0.02 mm |
Do You Need Core Sleeves?
Core sleeves are a maintenance component, not always required. Install them when:
✅ You're in the right place if:
- Mold runs 500K+ cycles and pin position bore shows wear
- Core pin has L/D ratio > 10 (long, thin pin that needs lateral support)
- Mold plate material is softer than the pin material (e.g. P20 plate with SKH51 pins)
🔄 Consider switching to:
- Pin runs fine without lateral support? → Core sleeves are not needed
- Need the core pin itself? → Straight Core Pins
- Need ejector function (pushing the part)? → Ejector sleeves are a different component (separate category)
About Core Sleeves
In high-cycle molds, repeated pin movement gradually wears the plate bore. Core sleeves act as a sacrificial wear interface — when the sleeve wears out, it is pressed out and replaced at a fraction of the cost of plate repair or re-machining.
A secondary but equally important function is precision guidance. Long, slender core pins (L/D ratio exceeding 10) are susceptible to deflection under injection pressure. The sleeve constrains the pin along its length, preventing lateral displacement that would cause uneven wall thickness in the molded part.
Core sleeves are recommended for molds running 500K+ cycles, pins with high L/D ratios, or applications where the mold plate material is softer than the pin material (risking bore enlargement).
Retrofitting core sleeves into existing molds is possible provided the plate bore can be enlarged to accept the sleeve's outer diameter while maintaining sufficient plate material around the bore.
Application Scenarios
See how this product type solves real engineering challenges across different industries and applications:
Annular Feature Formation
Pain point: Ring-shaped features like O-ring grooves, snap-fit rings, and annular channels require a sleeve-over-pin configuration — the sleeve forms the outer diameter while an inner pin forms the core.
Why it fits: Core sleeves provide the outer bore of annular features with precision-ground inner and outer diameters. Tight ID tolerance ensures proper fit over the inner core pin.
Tubular Connector Cavities
Pain point: Cylindrical connector housings require forming both the outer shell (via the sleeve) and the internal pin channels (via inner core pins) — with concentricity critical for electrical contact alignment.
Why it fits: Core sleeves maintain concentricity between inner and outer diameters to within 0.01 mm TIR. This ensures uniform wall thickness in thin-wall tubular molded parts.
Medical Tube & Cannula Cores
Pain point: Medical tubing and cannula components require biocompatible materials and ultra-tight wall thickness control — the sleeve-and-pin configuration must maintain concentricity across the entire length.
Why it fits: STAVAX ESR core sleeves provide corrosion resistance for medical resins. Precision honing of the inner bore ensures consistent wall thickness critical for fluid flow devices.
Related Categories
Frequently Asked Questions
How do core sleeves differ from ejector sleeves?+
When should I install core sleeves?+
Can I retrofit core sleeves?+
Engineering Resources
Case Studies
Need a Custom Quote?
Send your specifications — material, dimensions, quantity — and receive a quote. MOQ: 1 piece. Custom dimensions available.