JIS Standard SKH51 Steel Pin-Point Gate Bushings Round Gate Transition SR

This pin-point gate bushing variant is used in injection mold tooling to create a stable, well-controlled gate that feeds the cavity with minimal disruption. In automotive connector and sensor housing molds, the round gate transition helps maintain a smooth melt flow into the gate area, supporting repeatable filling during high-cycle production.

For consumer electronics and enclosure parts, the SR tip step shape is suited to producing consistent pin-point gate formation while helping reduce variability associated with gate trimming and early solidification. The SKH51 hardened wear construction supports long service life where the gate region experiences frequent thermal cycling and sliding/maintenance contact.

• Use the round transition to support stable melt flow and improved process consistency.
• Match SR tip geometry for reliable pin-point gate formation in the die.
• Rely on the ±0.01 P tolerance for precise gate alignment to the mold’s designed opening.

JIS Standard SKH51 steel is selected for pin-point gate bushing service because it combines high hardness with good wear resistance in the gate/transition region. It is commonly associated with AISI M2 tool steel equivalent performance, making it suitable where the gate bushing sees repeated injection cycles and abrasive wear from runner and gate material contact.

• Heat treatment: typically supplied in a hardened condition for wear resistance (the exact hardness value is not specified in the provided data).
• Hardness & trade-offs: hardened SKH51 improves wear resistance and dimensional stability under cycling, but like other high-speed steels, it may trade off some toughness compared with more ductile mold steels.
• Wear behavior: durable hardened wear construction supports reliable operation over repeated gate-forming cycles.

If alternate steels are required, choose based on the balance between wear resistance and toughness for your gate material and cycle rate; this SR SKH51 configuration is specifically intended for wear-focused gate bushing performance.

Select the bushing dimensions by matching the gate interface geometry to the mold cavity/core gate opening and the designed pin-point gate diameter. The P dimension tolerance is fixed at ±0.01, so the most critical interface diameter (P) should be chosen to align with the intended pin-point gate size while maintaining design intent.

• D (outer diameter): choose within 2 ~ 8 mm based on available bushing pocket clearance and support length.
• L (length): select from 6 ~ 20, 8 ~ 25, 10 ~ 40, 15 ~ 60 mm to ensure proper engagement and support in the sprue/gate layout.
• Tip geometry: use P (0.3 ~ 1.2 mm) plus R (0.4 ~ 4 mm) and the fixed A taper angle 1 ~ 3° to control gate formation.

When tight fit is required, treat P as the controlling functional dimension (±0.01) and verify surrounding pocket dimensions meet your assembly clearance. Tip straight tolerance is variable (0 to 0.2 or 0 to 0.05 depending on selection), so confirm the chosen tip straight specification aligns with your gate mold surface finish and alignment requirements.