A burr is an unwanted protrusion or raised edge left on the edge of a part by machining.
Burrs occur in all kinds of operations — cutting, drilling, parting, and more.
A Closer Look
A burr left in place can cause assembly problems, injure hands or damage other parts, and degrade appearance and quality.
A "deburring" (removal) step is therefore added where necessary.
How burrs form depends on tool wear, cutting conditions, and the sequence of operations.
Achieving machining that leaves few burrs reduces downstream deburring work, so choosing the right tools and conditions matters.