Stepped Ejector Pins �?With Engraving

Stepped ejector pins support the same three engraving types as straight pins: date code (interchangeable inserts, YYMM format), cavity number (laser-engraved, 1–999), and custom text/logo (up to 6 characters). The engraving is applied to the larger-diameter head section (D1), which provides more surface area for legible marking. Minimum head diameter for engraving is ø5mm for date code inserts and ø3mm for laser-engraved cavity numbers. The engraving mark transfers to the molded part at the ejection point, enabling per-cavity traceability in multi-cavity molds.

The engraving is on the tip face of the larger-diameter head section (D1) — this is the surface that contacts the molded part during ejection. The shaft section (D2) is never engraved because it passes through the mold plate bore and does not contact the part. For date code inserts, the insert is press-fit into a pre-drilled pocket on the head face. For laser-engraved cavity numbers, the marking is applied directly to the flat tip surface. The engraved characters are oriented to read correctly on the molded part (mirror-image on the pin tip).

Cavity number and text engravings can survive 1–2 re-grinds if the tip removal is minimal (under 0.1mm). Beyond this, the engraving becomes too shallow for legible part marking and must be re-applied ($5–10 per pin for laser re-engraving). Date code insert types are more durable — the insert pocket depth is 1.5–2.0mm, allowing multiple re-grinds before the pocket is compromised. However, after each re-grind, the pin length decreases, which must be compensated by adjusting the ejector plate stroke or shimming. MISUMI recommends replacing rather than re-grinding engraved pins when the tip wear exceeds 0.15mm.