JIS Standard Steel Ejector Punches Step Spring Reinforced

These step ejector punches are used in injection mold toolsets where the ejector needs stable penetration and straight alignment during high cycle counts. The spring-reinforced variant is particularly suitable when the punch face must resist deformation and maintain consistent travel under heavy ejection loads.

• Automotive connector and sensor housing molds: The single-stepped shank helps preserve predictable alignment, while spring reinforcement supports reliable ejection from deep ribs or stepped cavities.
• Appliance and industrial component molds: For long production runs, the optional WPC surface treatment helps reduce wear where polymer flash and repeated impact can degrade ejector edges.
• Medical device housings (feature-rich cavities): Select tip geometries (round, rectangle, radius rectangle, oblong, or double flatted round) to match part geometry and prevent point-loading on thin sections.

Choose a tip shape and size range that matches your core/cavity location to ensure even contact and controlled ejection.

This series offers two steel options: SKH51 equivalent (M2) and SKD11 equivalent (D2). SKH51 (M2) is typically selected for cutting-edge wear resistance in applications requiring stable performance at repeated cycles, while SKD11 (D2) is commonly chosen when durable, wear-resistant tooling steel is needed for ejector faces.

• Heat treatment state: Not specified in the provided data; select based on your process window and desired hardness/toughness balance.
• Hardness (HRC): Not specified in the provided data; confirm at incoming inspection or from your supplier’s material certs.
• Wear vs. toughness trade-off: In general, higher wear resistance steels tend to sacrifice some toughness; pair the spring-reinforced structure with the chosen grade to manage impact loading.
• Surface treatment: Available as None or WPC to further improve wear performance in demanding production.

Material selection should be coordinated with the polymer, ejection force, and cycle rate.

Select dimensions by matching the ejector punch shank and tip geometry to your mold’s guide system and the part ejection contact area. This series supports shank diameter D = 5 ~ 25 mm with a tolerance of +0.005/0, m5, so you must align your guide/bushing bore and shoulder features accordingly.

• Shank fit: Use D within 5–25 mm. The m5 tolerance indicates a tight fit; verify clearance against your guide pin bore to prevent binding during thermal expansion.
• Working length: Choose L = 40 ~ 70 mm based on required stroke, tie-bar/tool stack-up, and safe over-travel.
• Tip length/engagement: For B (tip length), select L or S to achieve the required engagement depth without excessive penetration.
• Tip dimensions: Tip dimension P ranges 2 ~ 18 mm and PC ranges 1.8 ~ 9 mm. Corner radius R is specified at 0.15 mm. Match tip shape (round, rectangle, oblong, double flatted round, radius rectangle) to the part’s ejection land.

Ensure the selected tip dimensions distribute load over the intended area to reduce localized stress and wear.