Precision Straight Ejector Sleeves
Straight tubular sleeves designed to eject circular ribs and bosses. Available in multiple heat treatments and premium tool steels for maximum sliding fatigue life.
Products in This Category
JIS Standard SKD61 Steel Straight Ejector Sleeves - Nitrided
Nitrided surface, high heat resistance.
JIS Precision Straight Ejector Sleeves (SKH51 Steel)
High toughness through-hardened High-Speed Steel.
Nitrided Ejector Sleeves Etched for Easy Identification
PCS standard, quick sizing.
JIS Standard M2 Steel Precision Straight Ejector Sleeves
Ultra-wear resistant, wire-cut & polished bore.
JIS Standard SKD61 Steel Nitrided Straight Ejector Sleeves
Fast delivery standard type.
SKH51 Steel Straight Ejector Sleeve Tapered Head T=4 mm
Tapered head thickness 4mm.
SKD61 Steel Nitrided Straight Ejector Sleeves - H13 Type Flat T4
Flat head configuration.
SKH51 Steel Precision Stepped Ejector Sleeves (ESVFX)
High alignment precision.
SKD61 Steel Nitrided Straight Ejector Sleeves | Type ESN Head T=4 mm
Standard T4 head type.
JIS Standard SKD61 Steel Nitrided Straight Ejector Sleeves - Concentricity 0.06
High concentricity variant.
SKH51 Steel Short Tapered Ejector Sleeves (T4 Head)
Short series for compact molds.
SKD61 Steel Short Straight Ejector Sleeves with Nitride Coating | Head T4
Nitrided head T4 short series.
SKD61 Steel Nitrided Straight Ejector Sleeves (ESNV) Head T=4 mm
ESNV series precision fit.
SKD61 Steel Nitrided Straight Ejector Sleeves | ESNV-LC
Long service life series.
JIS Standard SKD61 Steel Nitrided Straight Ejector Sleeves H7 Bore
Precision H7 bore tolerance.
Oversized Ejector Sleeves - Etched Identification
PCS oversized outer diameter variant.
JIS Standard SKD61 Steel Straight Ejector Sleeves Nitrided ESJBC
Fast turnaround series.
JIS Standard SKD61 Steel Straight Ejector Sleeves T4 Head Nitrided
Standard nitrided T4 head.
JIS Standard SKD61 Steel Straight Ejector Sleeves | Nitrided ESJL
Tight concentricity series.
Selection Matrix: Straight Sleeve Materials
Compare our three standard straight sleeve tool steel offerings to find the right match for your polymer and cycle-life demands:
| Material Grade | Surface Hardness | Working Temp | Best For |
|---|---|---|---|
| Nitrided SKD61 | 900-1000 HV (Surface) / 48-52 HRC (Core) | Up to 550°C | High-temp molds, hot-runner setups, corrosive plastics. |
| SKH51 (HSS) | 58-61 HRC (Through-Hardened) | Up to 300°C | High toughness, fine blanking, standard medical molding. |
| M2 (Premium HSS) | 61-64 HRC (Through-Hardened) | Up to 320°C | Highly abrasive materials (glass-fiber, carbon-fiber filled resins). |
Decision rule: Match sleeve material to your operating temperature and resin type. SKD61 nitrided offers the best cost-per-shot for most applications. For full material property comparison, see our Ejector Sleeve Material Guide.
Fitting Clearance and Tolerances
Understanding inner diameter (ID) and outer diameter (OD) clearances is essential to prevent sliding wear:
Concentricity and Guide Fit
The outer diameter (D) is ground to g6 (-0.005/-0.020mm) to allow a smooth guided fit within the mold plate. The inner bore (d) is finished to H7 (+0.015/0mm) to match the center pin OD, establishing a precision slip clearance.
Preventing Thermal Seizing
Under high temperatures, tool steels expand. SKD61 has a linear expansion coefficient of 11.7 x 10^-6/°C. We ensure a minimum clearance of 0.010mm to guarantee the sleeve travels freely even at 200°C mold temperatures.
Engineering note: Target clearance at the tight end of the acceptable range — natural wear increases clearance over time. For the complete calculation method with worked examples, see our Clearance Calculation Guide.
Application Scenarios: Where These Sleeves Excel
See how different materials and finishes solve specific molding engineering challenges:
Abrasive GF Polymers
Glass-fiber filled resins (like PA66+30%GF) cause severe abrasion along the parting line, leading to flash.
Why it fits: Through-hardened M2 steel sleeves at 63 HRC withstand abrasive sliding wear much longer than standard hot-work steels.
Medical Cleanrooms
Standard liquid lubricants cannot be used in cleanroom molding due to contaminate risks, leading to dry-run friction.
Why it fits: SKH51 sleeves can be custom DLC-coated, enabling lubricant-free, high-speed ejection cycles without core seizing.
About Straight Ejector Sleeves
Our straight ejector sleeves feature high-precision concentricity (≤0.015mm) and a surface finish of Ra 0.1µm inside the bore to minimize sliding friction and maximize tool cycle-life.
Frequently Asked Questions
Why should I choose nitrided SKD61 straight sleeves over standard SKH51 sleeves?+
What inner diameter tolerance classes are available for straight sleeves?+
How does high glass-fiber content plastic affect straight sleeve wear and coating choices?+
Engineering Resources
Need a Custom Quote?
Specify your required OD/ID dimensions, material (SKD61/SKH51/M2), surface treatment (nitrided/standard), and length. Custom tolerance upgrades to H6 bore available.