Gas Release Rectangular Ejector Pins

Rectangular gas release ejector blades provide 1.5–5.0 mm² of venting cross-section per pin, depending on the cross-section size and groove design. For a standard 4×2mm blade with dual flat-cut venting, the venting area is approximately 2.5 mm². This is 3–5× the venting capacity of a round gas release pin of equivalent cross-sectional area. The flat surface geometry of the blade makes venting groove machining more precise and consistent. For deep-rib applications where gas trapping is severe, the rectangular profile can be specified with full-length grooves for maximum venting capacity.

Yes — gas release rectangular pins are specifically designed for deep-rib applications where gas trapping is most severe. Ribs with depth-to-width ratios above 5:1 are particularly prone to gas trapping at the rib tip, causing burn marks (dieseling) and short shots. The gas release grooves run the full length of the blade, providing continuous venting from the rib tip to the ejector plate. For ribs deeper than 30mm, MISUMI recommends the collar-type gas vent blade with circumferential grooves, which provides higher venting capacity than flat-cut designs. Maximum blade length for gas release variants is 250mm.

The gas release groove surface finish is Ra 0.8–1.6μm (ground finish), which provides adequate gas flow while preventing resin flash into the groove. The groove depth is precision-controlled at 0.02–0.05mm with a tolerance of ±0.01mm. After 50,000–100,000 cycles, the groove may accumulate resin residue that reduces venting effectiveness — scheduled ultrasonic cleaning every 100,000 cycles is recommended. For corrosive resins (PVC, flame-retardant compounds), H13 nitrided material with TiN-coated grooves extends the maintenance interval to 200,000+ cycles.