A study of burr formation processes using the finite element method: Part II - The influences of exit angle, rake angle, and backup material on burr formation processes

Finite element models in orthogonal cutting are presented in order to exami ne the influences of exit angles of the workpiece, tool rake angles, and ba ckup materials on burr formation processes in 304 L stainless steel in part icular. Based on the metal-cutting simulation procedure proposed by the aut hors, a series of stress and strain contours and final burr/breakout config urations are obtained. The burr formation mechanisms with respect to five d ifferent exit angles are found, and duration of the burr formation process increased with an increase of exit angle, resulting in different burr/break out configurations. Based on the development of negative shear stress in fr ont of the tool tip, the tool tip damage, what is called "chipping," is inv estigated. Also, with fixed cutting conditions and workpiece exit geometry, the influence of the rake angle is found to be closely related to the rate of plastic work in steady-state cutting because the larger the rate of pla stic work in steady-state cutting, the earlier the burr initiation commence s. Furthermore, in order to effectively minimize the burr size, three cases of backup material influences on burr formation processes are examined. It is found that the burr size can be effectively minimized when the backup m aterial supports the workpiece only up to the predefined machined surface. [S0094-4289(00)01402-X].