Blade Free Flange-Position Ejector Pins

Blade-type free-flange ejector pins are available in standard rectangular cross-sections from 1.0×0.5mm up to 12×6mm (width × thickness). The most common sizes for injection mold rib ejection are 2×1mm, 3×1.5mm, 4×2mm, and 6×3mm. The free-flange collar accommodates the rectangular shank profile with a matching keyway to prevent blade rotation — critical for maintaining correct orientation relative to the rib feature. Custom cross-sections are available with 7–10 day lead time.

The flange lock mechanism on blade-type free-flange pins uses a split-block clamp design rather than the collet used on round-shaft free-flange pins. Two half-blocks clamp around the rectangular shaft profile and are secured by a through-bolt. The rectangular profile provides two benefits: (1) it prevents rotation (the flat faces lock against the block surfaces), and (2) it allows the flange to be repositioned along the shaft by loosening the through-bolt. Clamping force is rated for ejection loads up to 400N per pin — sufficient for most rib ejection applications.

Maximum blade length for free-flange pins is 200mm, compared to 300mm for standard fixed-head rectangular ejector pins. The shorter maximum is due to the free-flange clamp adding a compliance point that amplifies any lateral vibration during the ejection stroke. For blade lengths above 150mm, MISUMI recommends using a guided bushing at the plate exit to provide lateral support. Minimum blade length is 40mm. The blade length is configurable in 0.5mm increments within the catalog range.