Sources and scope for this page: Industry convention — no single governing standard (conventional usage, definitions vary between sources), covering the definition of built-up edge (bue). No independent source check is recorded for this page: the content rests on the sources listed and on the working shown on the page. How sources, methods and updates are recorded.
Definition
Built-up edge forms when pressure and temperature at the interface cause workpiece material to weld to the tool. It builds up, then breaks off, taking a piece of the edge with it — so the symptoms are fluctuating surface finish, inconsistent dimensions, and rapid tool wear.
It is commonest in soft, ductile materials at low speeds: low-carbon steel, aluminium, copper and austenitic stainless. The standard response is to raise the surface speed until the interface temperature is past the range where welding occurs, and to use a sharp, positive-rake edge with a polished face.
Common misuse
Trying to cure BUE by slowing down. Low speed is what causes it.