Custom Ejector Sleeves
Precision injection mold ejector sleeves manufactured to your exact drawings. Factory-direct with ±0.002mm tolerance, low MOQ, and fast lead times.
An ejector sleeve (hollow ejector pin) is a cylindrical mold component that slides over a core pin to eject molded parts. Unlike solid pins that apply point force, sleeves distribute 360° circumferential force around deep bosses, cores, and internal features — reducing distortion and improving ejection stability in high-cycle injection molding.
Custom Ejector Sleeve Types
GUNRI manufactures 8 major ejector sleeve categories — all configurable to your specifications
Straight Ejector Sleeve
JIS head, 19 product lines in DIN & JIS. Configurable OD/ID/L. SKD61 nitrided or SKH51.
Stepped Ejector Sleeve
Reinforced shoulder for high ejection force. SKH51, multiple head thicknesses, concentricity ≤0.005mm.
Thin-Wall Ejector Sleeve
Wall thickness down to 0.5mm. Vacuum-hardened SKH51 prevents cracking in thin-wall applications.
Micro Ejector Sleeve
OD from φ1.0mm for micro-injection molding. SKH51 with vacuum heat treatment for precision.
Long Ejector Sleeve
Up to 1000mm. Straightness ≤0.05mm for deep-core molds and large-part ejection.
Non-Standard / Custom Ejector Sleeve
Made-to-print per your drawing. Any OD/ID/head/stepped combo with tolerances down to ±0.005mm.
Carbide & Stainless Sleeve
Tungsten carbide / S136 stainless. For medical, cleanroom, and highly abrasive mold environments.
Coated Ejector Sleeve
DLC / TiN / Nitride coated. 2-3x longer life than uncoated. Friction coefficient <0.15 for high-speed molds.
Technical Specifications
Precision parameters across GUNRI’s material grades
| Parameter | SKD61 / H13 | SKH51 / M2 | 65Mn |
|---|---|---|---|
| Core Hardness | 38-42 HRC | 59-61 HRC | 48-52 HRC |
| Surface Hardness | HV 900–1100 (Nitrided) | 58-62 HRC (Through) | 55-60 HRC |
| Tolerance | ±0.01mm | ±0.005mm (max ±0.002mm) | ±0.01mm |
| Concentricity | ≤ 0.06mm | ≤ 0.01mm | ≤ 0.06mm |
| Max Length | ≤ 1000mm | ≤ 600mm | ≤ 600mm |
| Surface Treatment | Nitriding (ID + OD) | TiN / DLC / Nitride / Black Oxide | Nitriding / Black Oxide |
| Standards | DME, HASCO, MISUMI, PCS, DIN, JIS | DIN, JIS, HASCO | DME, MISUMI |
| Applications | General purpose, high-temp | High-wear, glass-filled, high cycle | Standard, economical |
Materials & Coatings
Select the optimal material and surface treatment for your application
SKD61 / H13
- Hot-work die steel, nitrided
- Core: 38-42 HRC, Surface: HV900+
- Excellent thermal shock resistance
- Length up to 1000mm
SKH51 / M2
- High-speed steel, through-hardened
- Hardness 59-61 HRC uniform
- 2-3x longer life than SKD61
- For glass-filled resins & high cycles
65Mn
- High-carbon manganese steel
- Excellent elasticity & fatigue resistance
- Economical for standard production
S136 / Carbide
- Martensitic stainless / tungsten carbide
- For medical, cleanroom, abrasive molds
- Maximum wear resistance
Nitriding
65-74 HRC on ID and OD. Precision ground after treatment.
TiN Coating
Titanium Nitride for reduced galling. Ideal for high-speed molds.
DLC Coating
Diamond-Like Carbon. Friction coefficient <0.15. Cleanroom safe.
Black Oxide
Anti-corrosion finish. Vacuum hardening available.
Customization Process
From your drawing to your production floor — transparent and reliable
Submit Drawing
STEP, STP, DXF, DWG, PDF
Engineer Review
Material, coating, tolerance check
Quote in 24h
Competitive pricing, clear lead time
Precision MFG
CNC grinding, heat treat, finishing
100% Inspection
Dimensional, hardness, concentricity
Global Shipping
Rust-proof, door-to-door delivery
Why Choose GUNRI?
18+ years of precision mold component manufacturing expertise
19 Product Lines
Straight ejector sleeves in DIN & JIS. Fully configurable.
Factory Direct
Manufacturer pricing. Quotes within 24 hours.
100% QC
Material certificates with every batch on request.
Fast Lead Time
5-15 days. Samples in 3-5 days.
Low MOQ
1 piece for prototypes. OEM/ODM available.
OEM Service
Custom branding, private labeling, drawing archives.
Standards Compatible
DME, HASCO, MISUMI, PCS, DIN, JIS.
Global Shipping
Rust-proof export packaging worldwide.
Common Ejector Sleeve Problems We Solve
Engineered solutions for real-world injection molding challenges
Sleeve Sticking / Seizing
Poor concentricity or insufficient clearance causes the sleeve to bind on the core pin. GUNRI controls concentricity to ≤0.01mm with radial clearance of 0.008–0.02mm. Fine grinding (Ra ≤0.4μm) and nitriding ensure smooth, consistent movement even at high cycle rates.
Sleeve Cracking / Breakage
Wall thickness ≤0.8mm with improper material hardness leads to early cracking. GUNRI recommends vacuum-hardened SKH51 (HRC 58–62) for thin-wall sleeves. Our heat treatment process eliminates brittleness while maintaining core toughness.
White Marks / Scratches on Parts
Rough sleeve surfaces transfer imperfections to molded parts. We offer fine grinding (Ra ≤0.4μm), mirror polishing (Ra ≤0.2μm), and superfinishing (Ra ≤0.1μm) for medical, optical, and cosmetic molds.
Short Service Life
Standard sleeves wear quickly in glass-filled or high-cycle molds. GUNRI’s TiN/DLC-coated SKH51 sleeves deliver 2–3x longer life than standard SKD61, with documented performance exceeding 1.5 million cycles in demanding applications.
Mold Types We Serve
Precision ejector sleeves for a wide range of injection mold applications
Connector Mold
High-precision electronic & automotive connector tooling with tight tolerance requirements
Cap & Closure Mold
Multi-cavity high-speed closure & bottle cap molds requiring long-life coated sleeves
Automotive Mold
Headlamp, connector & housing molds with glass-filled resins, DLC-coated for wear resistance
Electronics Mold
Precision thin-wall connector & housing molds for consumer electronics & micro components
Medical Mold
Syringe, diagnostic & surgical device molds using S136 stainless for corrosion resistance
Thin-Wall Molding
High-speed thin-wall molds for packaging, food containers & disposables requiring precision sleeve ejection
Customer Success Story
Real results from a precision ejector sleeve upgrade
Glass-Filled PBT
Connector Mold
From 200,000 to 1,500,000 Cycles — No Failures
A German automotive tier-1 supplier was experiencing ejector sleeve galling after just 200,000 cycles on a glass-filled PBT connector mold. The sleeves were sticking, causing 15 minutes of downtime per shift for manual cleaning and re-lubrication.
GUNRI proposed DLC-coated SKH51 sleeves with nitrided IDs and optimized radial clearance of 0.015mm. The result: over 1.5 million cycles without a single failure, a 20% reduction in cycle time due to lower ejection friction, and zero unscheduled downtime.
Standards Compatibility
Compatible with all major industry standards
DIN ISO 8405JISGBAISIASTM
Frequently Asked Questions
Related Products & Resources
Get a Quote for Your Custom Ejector Sleeves
Send your drawing now — we’ll review and reply with pricing and lead time within 24 hours.