glossary
Gross Fracture — Glossary Entry
Definition of gross fracture in industrial cutting: complete break of a knife, usually catastrophic and immediate. The rarest but most expensive failure mode.
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Gross Fracture is the complete break of a knife into two or more pieces, usually caused by an impact event (foreign object, dropped knife, misaligned stock) on a brittle substrate. Gross fracture is the rarest industrial cutting failure mode but the most expensive — a 600 mm shear blade that breaks in service costs €800–2,000 in scrap plus the downtime.
Common causes
- Foreign object in substrate (metal fragment, stone, glass)
- Knife dropped during change-over
- Misaligned stock forcing the knife
- Brazed joint failure on a tipped knife
- Heat-treat quench crack that propagated in service
How to detect before failure
- Quarterly metallurgical audit of 1 random knife from the rotation
- Visual inspection under 10× loupe for surface cracks
- Dye-penetrant or magnetic particle inspection on critical blades
- Replace knives at the end of their design life, regardless of visual condition
See also.
