The effect of beam geometry on diode laser forming of sheet metals

Laser beam forming has emerged as a new and very promising technique to form sheet metal by thermal residual stresses. One of the advantages of laser beam forming compared to conventional flame bending is its ability to accurately control the size and geometry of the heat source. In the area of optics, many studies explain the methods and design approaches to produce a variety of beam shapes such as line, rectangular, star, D-shape, annular, cross, etc. The objectives of this work are to compare the orientation effect of the rectangular beam, and to compare circular and rectangular beam geometries, for laser bending of AISI 304 stainless steel sheets. To achieve this, a high power diode laser (HPDL) is used to obtain bending angle for sheets of various thicknesses. From the study of the orientation of the rectangular beam, it is found that a narrow beam orientation produces higher bending angle. This is due to higher temperatures generated because of longer beam-material interaction. Comparing the circular beam with the rectangular beam, for the same average beam intensity, the circular beam produces higher bending angle.