Wire Edge — Industry Glossary Entry

Wire Edge is a thin, fragile burr on the very tip of the cutting edge, typically 1–5 µm thick and 0.5–1 mm long, caused by a re-grind that did not include spark-out passes. A wire edge peels off in the first 50–100 cuts and is mistaken for “the knife is dull” or “the steel is wrong”.

How to detect

• Visual under 10×: a bright thin lip on the back face at the very tip
• Touch the edge against a glass slide: the wire edge catches and bends
• Microscope at 50×: clearly visible as a thin flap

Fixes

• Re-grind with 2–3 spark-out passes at the final infeed
• Use a softer-bond grinding wheel (the wheel should “dress” the edge, not load)
• Replace the wheel if it is glazed or loaded
• Use a felt wheel with 1 µm diamond paste for the final pass on a precision slitter

See also.