Straight Ejector Pins — With Engraving

Three engraving types are standard: (1) Date code — interchangeable inserts for year/month marking, typically using YYMM format. The insert rotates to update the date each production run. (2) Cavity number — permanent laser-engraved numbers (1–999) on the pin tip face, transferred to every molded part for traceability. (3) Logo/text — custom text or logos up to 6 characters, laser-engraved for part identification or branding. Date code inserts are the most common (60% of engraving orders) because they provide automatic date tracking without mold disassembly.

Standard engraving depth is 0.05–0.10mm for cavity numbers and text, which provides clear part marking without significantly weakening the pin tip. Date code inserts have a raised character height of 0.3–0.5mm for deep, legible marks on the molded part. Maximum engraving depth for custom work is 0.2mm — beyond this, the stress concentration at the engraving edges risks tip chipping under repeated ejection loads. Minimum pin diameter for legible engraving is ø3mm; below this, character resolution becomes unreliable.

Laser engraving has minimal impact on pin strength. The heat-affected zone (HAZ) from laser processing is only 0.01–0.02mm deep, and the bulk hardness (HRC 60–62 for M2, HV 900+ for nitrided H13) is unchanged. For date code insert types, the pin tip is pre-drilled to accept the insert, which does reduce the tip cross-section by approximately 15–20%. This is compensated by using a larger pin diameter — MISUMI recommends ø5mm minimum for insert-type date codes. Cavity number and text engravings (surface-only) have no measurable effect on pin life or ejection force capacity.