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

Numerical Simulation and Experimental Validation of Sheet Laser Forming Processes Using General Scanning Paths

“…Nevertheless, in the present analysis, this definition is extended to properly take into account the effect of the width and step values, as LE = P ( w + s )/( v T s ). Figure 9 plots the bending angle in terms of the line energy for the studied cases where, in general, as reported in the literature [ 13 , 22 , 32 ], a direct correlation between these two variables can clearly be appreciated. However, some particular cases that do not exactly follow this trend can be identified, cases with the same line energy and transversal velocity values that lead to different bending angles (cases 1 and 7 for LE = 132 J/mm and v T = 5 mm/s, and cases 2 and 8 for LE = 66 J/mm and v T = 10mm/s) and the cases that exhibit a similar bending angle but were obtained with different line energy values (cases 3 and 6).…”

“…To this end, the computed bending angles at the start and end points of the free edge of the plate after five irradiations for the studied configurations are firstly compared in Table 2 with the corresponding experimental measurements (the comparison at the middle point is not included because of the practical difficulty to measure it). It is seen that, as the internal radius increases, the strain hindrance effect [ 13 , 17 ], which indicates how difficult it is to generate distortion in the plate, is less apparent, denoting that the geometric arrangement of the material surrounding the laser path directly affects the amount of bending of the different plate configurations. Overall, a good agreement between the experimental and numerical results is achieved.…”

“…The multiple circular scanning path applied to five semicircular geometric configurations, specifically varying their inner radius, is shown in Figure 3 a. In this case, a Yb fiber laser (IPG, Photonics, YLR-200-AC-Y11-Y13 rev 05 Model, 1.07 µm wavelength, multimode fiber, M 2 = 1.2) (IPG Photonics, Oxford, MS, USA) was employed, with the experimental setup depicted in Figure 4 [ 13 ]. It was composed of the following elements: the laser collimator (IPG Photonics, Oxford, MS, USA) and a platform to which the AISI 304 stainless steel sheets (0.6 mm thickness, all with an external radius of r out = 50 mm) are supported at their inner edge.…”

“…The solution of the thermomechanical formulation is tackled in the context of the finite element method via an in-house code [ 6 , 13 , 22 , 30 , 31 , 32 ], extensively validated in many engineering applications including traditional and laser forming problems. For the different plate configurations, the corresponding meshes are different (see Figure 7 ).…”

“…Furthermore, the relation between the number of irradiations and the desired curvature is successfully compared using a proposed analytical model. Navarrete and Celentano [ 13 ] carried out a numerical-experimental analysis related to multi-pass linear and curved scanning patterns, identifying a noticeable spring-back effect in circular sheets with curved scan paths, which decreases the final bending angle in comparison to the rectangular sheets with linear scans of equivalent lengths. Hoseinpour Gollo et al [ 14 ] determined, through numerical, experimental, and statistical analyses, the influence of the main laser parameters on the sheet deformation, finding that both the multi-pass configuration and scan velocity have a more relevant effect than the laser beam power.…”