Effect of workpiece geometry using circular scan patterns in sheet laser forming processes

摘要

This research reports on the effect of workpiece geometry using circular scan patterns in low output power multi-pass laser forming processes applied to graphite coated AISI 304 stainless steel 0.6-mm-thick sheets. Curved plates, both circular and ring sectors, with multiple circular concentric laser path irradiation have been bent applying a fiber laser beam of diameter 1.2 mm, power 27 W power, and moving with a scanning velocity of 10 mm/s. Their behaviors are compared with those of rectangular plates linearly irradiated. In order to study the different variables that affect the bending plates with circular and linear patterns, finite element simulations of the forming processes have been carried out. Geometrical experimental measurements validate this formulation which, in turn, provides information about evolutions of the temperature, strain, and stress fields in the plate. A noticeable spring-back effect has been predicted for the curved sheets where, in addition, a direct relationship between equivalent plastic strain and bending angle could not be established. In such situations, the geometric shape of the plates was found to have a marked influence on the plate deformation.