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.