glossary
Flatness — Industry Glossary Entry
Definition of flatness in industrial blade measurement: the deviation of a face from a perfect plane, and how flatness affects the contact area between knife.
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Flatness is the deviation of a knife face from a perfect plane, measured in millimetres. On a slitter, flatness affects the contact area between the knife and the anvil; on a shear, it affects the contact with the workpiece.
Typical flatness by application
- Precision slitter: ≤ 0.005 mm across full face
- Standard slitter: ≤ 0.010 mm
- Shear blade: ≤ 0.020 mm across the cutting length
- Long shear blade (≥ 1 m): ≤ 0.030 mm across the full length
How to measure
- Place the knife on a precision surface plate
- Insert feeler gauges under the high points
- Read the maximum gauge that fits
- A knife that rocks on the plate is not flat
See also.
