Burrs are raised or feathered material left at the cut edge. Ductile materials may form long whiskers, while brittle materials may chip or leave a rough fractured edge.
Blunt cutting edges, incorrect punch-to-die clearance, unstable fixtures, excessive tool runout, and unsuitable part temperature are typical causes. The best condition differs between shearing, routing, sawing, and die cutting.
Corrective action
The burr side and direction should be recorded because they identify where the material is being pushed rather than cut. Tool sharpness and alignment should be verified before process settings are changed. Support must prevent the wall from flexing away from the cutter.
Deburring should not become the primary production solution when the edge can be generated cleanly. Secondary scraping or flame treatment can alter dimensions, gloss, and stress and should be controlled as a separate qualified process.