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Ejector Sleeves for Die Casting

H13 (SKD61) nitrided ejector sleeves for annular ejection around core pins. Engineered for tubular, boss, and through-hole features in aluminum and zinc die castings.

Products in This Category

Straight Ejector Sleeves — H13 Nitrided

Standard wall thickness. Inner Ø4–Ø20 mm, Outer Ø6–Ø25 mm. Selectable lengths.

Ejector Sleeve vs Ejector Pin — When to Use Which

FactorEjector PinEjector Sleeve
Part FeatureFlat surface, solid sectionTubular bore, boss, through-hole
Ejection SurfaceCircular disc (pin tip)Annular ring (sleeve face)
Interior Surface MarksN/A (no interior)No marks on hole interior
Works With Core PinsCannot surround coreSlides over core pin
Maintenance ComplexitySimple replacementMust match core pin OD
Cost$$$
Decision Rule: If the casting feature is a hole or boss formed by a core pin, always use an ejector sleeve. Using an ejector pin would require either piercing the part wall or placing the pin off-center, both of which create defects.

Decision rule: Use ejector sleeves for tubular features (bosses, standoffs) where the sleeve slides over the core pin. Use ejector pins for solid features where single-point ejection is sufficient. For detailed guidance, see our Ejector Sleeve vs Ejector Pin for Die Casting — When to Use Which.

Application Scenarios

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Die Cast Boss Ejection

Mounting bosses in aluminum housings formed by core pins. The sleeve ejects the boss uniformly without distorting the bolt hole.

The sleeve slides over the core pin with H7 clearance, applying uniform ejection force around the entire boss circumference — preventing the tilting and cracking that occurs when a single-point pin tries to eject a tubular feature.

Key spec: Wall thickness ≥ 1.5 mm for boss heights > 15 mm

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Connector Port Ejection

Through-hole ports in electronic enclosures. Sleeve provides clean ejection without marks inside the connector receptacle.

Key spec: Inner diameter matched to port core pin ±0.01 mm

Decision rule: Sleeve ID must match core pin OD with 0.01–0.02 mm/side clearance to prevent aluminum intrusion. For deep bosses (L/D > 3), specify guided sleeves to prevent deflection. For detailed guidance, see our How to Prevent Aluminum Seizure Inside Ejector Sleeves.

About

1 product series. H13 (SKD61) vacuum heat-treated to 44–48 HRC, ion-nitrided to 900–1,100 HV. Inner bore nitrided for anti-soldering protection.

H13 NitridedJIS

Frequently Asked Questions

When should I use an ejector sleeve instead of an ejector pin in die casting?+
Use ejector sleeves when the part has a boss, tube, or hollow cylindrical feature that must be ejected from around a core pin. The sleeve slides over the core pin and pushes the part off the core surface. Common applications: threaded bosses, dowel holes, and mounting posts in aluminum die castings. If the feature is a solid flat surface, use a standard ejector pin instead. Sleeves are more expensive and require tighter bore tolerances than pins.
What inner/outer diameter combinations are available?+
Standard catalog covers inner diameters from Ø4 to Ø25 mm and outer diameters from Ø6 to Ø32 mm. Wall thickness ranges from 1.0 mm (minimum for structural integrity under die casting pressures) to 3.5 mm. Custom ID/OD combinations are available for non-standard core pin diameters. Critical dimension: the sleeve inner bore must be ground to H7 tolerance to maintain sliding clearance with the core pin while preventing molten metal intrusion.
How do I prevent aluminum from seizing inside the sleeve bore?+
Three strategies: (1) Maintain sleeve-to-core clearance at 0.005–0.015 mm — too tight causes galling, too loose allows flash intrusion; (2) Apply release agent specifically to the sleeve bore area during die spray; (3) Use nitrided H13 sleeves — the nitrided surface (900+ HV) resists aluminum soldering significantly better than uncoated steel. If seizure has already occurred, remove the sleeve, clean with sodium hydroxide solution to dissolve aluminum deposits, and polish the bore before reinstalling.

Engineering Resources

Comparison Guide

Ejector Sleeve vs Ejector Pin for Die Casting — When to Use Which

Decision criteria and design examples for choosing between pins and sleeves.

Troubleshooting

How to Prevent Aluminum Seizure Inside Ejector Sleeves

Root causes of sleeve-bore seizure and 5 proven prevention techniques.

Need Die Casting Ejector Sleeves?

Specify inner diameter (core pin OD), outer diameter, length, and casting alloy.

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✓ H13 nitrided bore✓ MOQ 1 piece