Runner Ejector Sets
Complete runner ejector assemblies with sucker pins for reliable runner removal in three-plate mold operations.
Products — 1 Variants
Runner Ejector Sets for Three-Plate Molds
Runner Ejector Sets for Three-Plate Molds
How Runner Ejector Sets Work
Operating Sequence
Runner ejector sets use a sucker pin mechanism that works in two phases during the mold opening cycle:
- First opening (gate separation) — The sucker pin's undercut grips the runner, holding it in the runner plate while the cavity plate separates. Pin-point gates shear cleanly.
- Second opening (runner ejection) — The runner plate opens further. The ejector mechanism pushes the runner off the sucker pin, and the runner falls free from the mold.
Key Advantage
Unlike standard ejector pins that simply push, sucker pins provide a grip-then-release action. This ensures the runner stays in the correct plate during gate separation and only ejects during the runner drop phase.
Engineering note: Ejection stroke must be sufficient to fully clear the runner from the runner plate. See our Runner Ejector Sets Technical Guide for stroke calculation.
Dedicated Ejector Set vs. Standard Ejector Pins
✓ Use dedicated runner ejector sets when:
- You need grip-and-release action for reliable runner holding during gate separation
- Runner tends to stick in the runner plate after gate shearing
- Production requires consistent, automated runner drop without operator intervention
🔀 Consider standard ejector pins when:
- Your runner drops freely by gravity after gate separation
- The mold has existing sucker pin features machined into the runner plate
- Budget is limited and runner ejection is not problematic
About Runner Ejector Sets
Runner ejector sets are purpose-built assemblies for three-plate mold runner handling. Each set includes a sucker pin, spring, and housing that install as a unit into the runner plate. The sucker pin's undercut geometry is calibrated to grip common runner cross-sections without interfering with resin flow during injection.
Application Scenarios
Runner ejector sets are most valuable in these situations:
Automated Three-Plate Mold Production
Fully automated cells where runner must drop cleanly every cycle without operator assistance.
The grip-and-release mechanism ensures consistent runner ejection timing, preventing runner jams that stop the automated cycle.
Sticky Resin Runner Problems
Resins with high mold adhesion (PA, POM, TPU) cause runners to stick in the runner plate after gate separation.
The sucker pin's undercut provides positive retention during gate separation, then the spring-loaded ejector overcomes adhesion forces during runner drop.
Engineering Resources
Need a Custom Quote?
Specify your runner plate thickness, runner cross-section, and mold opening stroke distance. We will confirm ejector set compatibility.