In engineering, a burr refers to the raised edge on a metal part. It may be present in the form of a fine wire on the edge of a freshly sharpened tool or as a raised portion on a surface, after being struck a blow from an equally hard, or heavy object. More specifically, burrs are generally unwanted material remaining after a machining operation such as grinding, drilling, milling, or turning. Burr formation in machining accounts for a significant portion of machining costs for manufacturers in America and around the world. Drilling burrs, for example, are common when drilling almost any material. The Boeing 747 airplane has approximately 1.3 million holes drilled in it, most of which have to be deburred to some extent. As one could imagine, the cost and time needed to perform these drilling and deburring operations is significant. In addition to drilling, milling is also a source of burr formation in machining. One good example of unwanted burrs is in the automotive industry where cylinder blocks, pistons and other engine components are cast then milled to a specific dimension. With higher and higher demands placed on accuracy and precision, burr formation is of critical importance because it can affect engine performance, reliability, and durability. Dr. David Dornfeld at the University of California at Berkeley and the Laboratory of Manufacturing and Sustainability (LMAS) are leading researchers of burr formation. They lead a group known as the Consortium of Deburring and Edge Finishing (CODEF) at Berkeley which addresses many burr formation problems that industry is facing.
