Investigation of the Profile of Laser Bends with Variable Scan Distance

Laser forming is a process capable of bending sheet metal only with the laser beam and without a physical interaction with the part. The part is formed by small and local deformations by the laser beam and it is done in increments with each pass of the laser. This incremental forming makes it difficult to ensure a smooth deformation field, which can result in non-smooth components and difficulties in achieving the required tolerance of the bends. This work presents an experimental investigation of the effect of varying the scan distance, number of passes per scan line and number of scan lines on profile of a v-bend. The v-bends were measured on both sides by a laser range scanner to determine the surface profile along the bend. To evaluate the quality of the vbend and define the profile as discrete or continuous, the bend roundness was evaluated manually and automatically by a Least Squares Circles method and by using second order differentiation method. The effect of varying the scan distance was tested experimentally on five samples with 16 mm and five samples with 20 mm bend length. The parts were subsequently evaluated on both the inside and outside of the bend and the bend angle was measured. The results show good correlation between the manual inspection and the automatic examination. The results show that the overlapping of the laser beam paths is required to create a continuous smooth bend.