Stepped Ejector Sleeves
Stepped shaft hollow sleeves for long ejector strokes. Guided shoulders ensure high column rigidity while limiting sliding contact wear.
Products in This Category
JIS Standard M2 Steel Precision Stepped Ejector Sleeves
High-speed steel stepped shaft, wire-cut bore.
SKH51 Steel Precision Stepped Ejector Sleeves (ESVF)
Thin-walled guide layout, high strength.
JIS Standard SKH51 Steel Precision Stepped Ejector Sleeves
Thin-wall bearing structure.
ESNF Type Stepped Ejector Sleeves | SKD61 Hardened Steel Nitride Coated
Hardened ESNF nitrided sleeves.
JIS Standard SKH51 Steel Precision Stepped Ejector Sleeves | Ground Boring
Ground boring concentric alignment.
JIS Standard SKD61 Steel Stepped Ejector Sleeves, Nitride Coated
Fast delivery stepped variant.
JIS Standard Stepped Ejector Sleeves Nitride Coated | SKD61 Steel
Nitrided hot-work steel stepped.
JIS Standard SKD61 Steel Stepped Ejector Sleeves with Nitride Coating
Configurable step length.
Japanese Standard SKD61 Steel Stepped Ejector Sleeves with Nitrided Surface
Wear-resistant stepped casing.
JIS Standard Stepped Ejector Sleeves (SKD61 Equivalent) Nitrided
High-quality cost-effective alternative.
Selection Matrix: Stepped Sleeve Series
Compare the dimensions and design standards of our primary stepped ejector sleeve offerings:
| Series Type | Steel material | Guiding Section | Heat Treatment |
|---|---|---|---|
| ESVF (Precision) | SKH51 (HSS) | Precision ground guide length | Through-hardened 58-61 HRC |
| ESNF (Standard) | SKD61 (Hot-Work) | Standard guide length | Surface nitrided 900+ HV |
Selection tip: Match sleeve material to your resin type — use STAVAX for corrosive resins (PVC, POM) and SKD61 nitrided for glass-filled resins. For the complete material-resin pairing matrix, see our Ejector Sleeve Material Guide.
Troubleshooting: Stepped Sleeve Failure Modes
Refer to the table below to diagnose and resolve stepped sleeve failures in your molds:
| Common Problem | Root Cause | Engineering Solution |
|---|---|---|
| Fatigue cracking at shoulder step | Sharp corners build up localized stress concentration during long ejector stroke cycles. | Specify sleeves with optimized, stress-relieving shoulder transition R angles (R ≥ 0.5mm). |
| Sleeve guide seizure (Lock-up) | Inadequate guide bore clearance in mold plates or loss of lubrication. | Verify g6 tolerance on OD. Apply specialized PVD coating or switch to DLC lubrication-free. |
Engineering note: Most stepped sleeve failures originate at the shoulder radius. Increasing the fillet from R0.2 to R0.5 can triple fatigue life. For detailed analysis, see our shoulder breakage analysis.
Application Scenarios: Stepped Ejector Sleeves
Targeted scenarios where stepped sleeve architectures prove critical:
Medical Cleanrooms
Medical syringes require high-speed ejection. Dry-sliding conditions are mandatory to prevent lube contamination.
Why it fits: Through-hardened HSS ESVF sleeves are ground to extremely tight tolerances, allowing dry-running without seizing.
Optical Component Molding
Optical components cannot tolerate ejector pin misalignment, which causes visual lens parting line defects.
Why it fits: Stepped guide shoulders restrict radial runout to ≤0.010mm, guaranteeing flawless visual surfaces.
Frequently Asked Questions
What step ratios and shoulder dimensions are standard for ESVF and ESNF sleeves?+
How does a nitrided surface finish affect stepped sleeve operating temperatures?+
What tolerance class is applied to the outer diameter of stepped sleeves?+
About Stepped Ejector Sleeves
Stepped ejector sleeves (ESVF, ESNF series) provide a transition from a larger guide diameter to a smaller molding-end diameter. The step shoulder reduces plate contact friction and increases structural rigidity, but requires careful attention to the shoulder transition radius to avoid stress concentration failures. Available in SKD61 (nitrided) and SKH51 (through-hardened) options.
Engineering Resources
Need a Custom Quote?
Specify step diameters, shoulder R-angle, material, and surface treatment. DLC and TiAlN coatings available for cleanroom applications. Custom step ratios on request.