JIS Standard SKD61 Steel Straight Ejector Sleeves

These straight ejector sleeves are used inside injection molds to guide ejector pins and maintain straight-line movement during opening cycles. The nitrided SKD61 surface treatment is well-suited to applications where sliding contact repeatedly occurs, such as automotive connector and sensor housings, where consistent guidance helps reduce eccentric wear and maintains stable ejection.

They also fit consumer appliance and home-automation housings that cycle frequently at high clamp-to-open speeds. The controlled concentricity (hole-to-shaft ≤0.06) supports reliable centering of the guidance bore, which helps limit binding when tolerances stack across multiple ejector components.

• Configurable lengths (L = 40–200, 40–250, 40–300, 40–500, and 500.1–800) allow designers to match cavity depth and ejection travel.
• JIS head (6 mm or 8 mm) helps ensure proper seating and repeatable alignment in the ejector system.

This product uses JIS SKD61 steel, commonly aligned with the widely referenced H13 family for hot-work die steels. The nitrided surface treatment is intended to increase surface hardness and wear resistance while keeping the core tougher to handle shock loads from ejection events.

• Heat treatment state: nitrided surface (base SKD61 steel), improving abrasive and adhesive wear at the sliding interface.
• Performance trade-off: nitriding prioritizes surface durability and reduces galling risk, while toughness remains largely governed by the SKD61 substrate.
• Wear vs. toughness: compared with through-hardened materials only, nitriding focuses hardness near the surface, helping preserve impact resistance.

For maximum guidance life where repeated sliding and debris exposure occur, the nitrided SKD61 combination supports stable operation under cyclic molding loads.

To select the correct straight ejector sleeve, match the sleeve bore/shaft designation to the ejector pin and then confirm the sleeve length for guidance engagement. The shaft diameter range is D/P = 3.5 to 20 mm with a shaft diameter selection method using 0.01 mm increments.

• Choose V (hole diameter) = 1.5 to 3 mm and verify the S (V hole diameter length) = 20–100 mm, 20–150 mm to ensure the pin support length is adequate.
• Select the required L (40–200, 40–250, 40–300, 40–500, or 500.1–800 mm) based on mold thickness and expected ejection travel.
• Verify the shaft diameter tolerance selection: -0.01/-0.02 or -0.01/-0.03 (as specified by the product option).

For fit, use the specified H7 inner diameter tolerance and the JIS head geometry to seat the sleeve reliably. If multiple ejector components contribute to stack-up, confirm that the ≤0.06 mm hole-to-shaft concentricity aligns with your centering requirements to avoid binding.