Abstract: This paper classified the forms of forward burrs in metal cutting on the basis of the cutting motion and tool outting edges.The principles of forming and the main influencing factors of forward burr are studied,and the related theories are analyzed.Thus a clear understanding of the types, and the forming process of the burrs is obtained. The physical quantity of determiuing the tear of forward burr-limit depth of cut α_pr-is given. A oertain number of measures and new restraining methods to control and decrease the forward burrs are advanced.

Key words: machining, limit depth of cut, deburring technology, forward burr