Technical Guide3 min read

How to Handle Step Transitions in Free-Flange Ejector Pins

Key Takeaway: The free-flange collar must be positioned above the step transition (on the shaft side, not the tip side). The distance from collar to step must equal the support plate thickness ±0.5mm.

Correct Positioning

The step transition (where D2 meets D3) must align with the plate bore transition. The free-flange collar sits in the ejector plate counterbore, and the shaft passes through the support plate. The step transition must occur at the support plate face — positioning the collar too high or too low shifts the step out of alignment with the plate bore transition, causing binding.

Calculation

Collar position from tip = total pin length − ejector plate thickness − support plate thickness. Verify by assembling the mold with the ejector plate at home position and checking that the step transition aligns with the support plate face.

Frequently Asked Questions

What happens if the step is misaligned with the plate transition?+

If misaligned by more than 0.5mm, the pin will bind during the ejection stroke. The larger shaft diameter enters the smaller bore, causing jamming and potential pin breakage.

Can I adjust the step position after installation?+

The step position is fixed (machined into the pin). Only the free-flange collar position is adjustable. If the step position is wrong, a different pin with the correct step location must be ordered.