· KAIPU Engineering · glossary · 1 min read
undefined — Industry Glossary Entry
Definition of rake angle (also called rake, top rake or cutting rake) in industrial cutting: the angle of the front face of the cutting edge measured from vertical, and how positive vs negative rake affects cutting force, chip flow and blade life.
undefined is the angle of the front face (the face that contacts the substrate first) of an industrial cutting edge, measured from a line perpendicular to the cut. A positive rake angles the face away from the cut, reducing the cutting force; a negative rake angles it into the cut, increasing the force but improving edge strength.
Rake angle, by substrate
- Paper and film: +5° to +15° (positive, to reduce cutting force and prevent drag)
- Plastic film: +10° to +20° (more positive for clean cut)
- Soft plastic, rubber: +15° to +25° (very positive, to slice rather than drag)
- Plate shearing: 0° to +3° (near-neutral, for edge strength on impact)
- Stainless plate: -3° to +3° (neutral, for wear balance)
- Hardened steel / AR plate: -5° to -10° (negative, for edge support)
Common mistakes
- Too much positive rake on a thin knife: the edge deflects, burr grows.
- Too much negative rake on a tough substrate: the cutting force is too high, the knife chatters, the substrate work-hardens.
- Asymmetric rake: the knife cuts in a curve instead of a straight line.
See also: Clearance angle, Hone (micro-hone), Burr.