Side Clearance — Glossary Entry
Definition of side clearance in industrial cutting: the angle that lets the substrate separate from the knife after the cut, on circular and rectangular.

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Side Clearance is the relief angle on the side faces of a circular slitter or a rectangular knife that lets the cut substrate separate cleanly from the body of the knife. Without side clearance, the substrate drags on the knife body and the cut tears or wrinkles.
Typical side clearance
- Paper, film: 0.5–1.0° per side
- Tissue: 1.0–1.5° per side (more relief for the softer, thicker substrate)
- Plastic, rubber: 1.5–3.0° per side
- Plate shear: not applicable (single-pass cut)
How to specify
On a circular slitter, side clearance is the included angle between the two side faces of the disc. A 250 mm OD × 25 mm × 3 mm slitter with 1° per side clearance has a side taper of 4.4 mm over the 25 mm thickness — the OD at the centre of the thickness is 4.4 mm smaller than at the edges. The re-grind shop must restore this taper every cycle.
See also.



