Formatura laser di manufatti in acciaio inossidabile a geometria complessa

High power diode laser is potentially attractive in several manufacturing domains. Transfer efficiency by far higher than competitors, long lasting source, easy setting-up and automation, lack of maintenance as well as moderate investment and running costs make diode laser extremely promising in forming process. Available technologies are numerous, but laser forming has the advantages of limited springback, lack of molds and sophisticated auxiliary equipment. Nevertheless, the achievement of complex shape with high dimensional accuracy and precision by forming with diode laser is still poorly investigated. The nearly unpredictable influence of the material properties and initial geometries on the final shapes and the need for composite forming strategy has up today discouraged the accomplishment of systematic investigations. In order to bridge the gap, 3d forming strategies of flat stainless steel substrates with variable shapes by high power diode laser is herein investigated making use of Design of Experiment (DoE). The strongly innovative aspect of the work is related to the use of a high power diode laser as “thermic tool” to generate the bend in the metal sheet, using the thermal stresses generated in the material by laser irradiation. The research has first provided a study of the laser bending on different linear scanning geometries, then go on to address the problem of the study of 3D forming, both on curved scanning geometries that for right bending angles; finally it was studied the achievement of sharp bending angles with small fillet radius. As part of the studies and experiments, the order that was followed, is therefore: - Linear laser bending study for different scanning geometries; - 3D Laser forming for curved scanning geometries; - 3D Laser forming mechanically assisted by bending at a right angle; - 3D Laser forming mechanically assisted by bending at a sharp angle. For each experimental study, 3D shape objects were also obtained, whose bending angles were measured by means of a Coordinate Measurement Machine (CMM) and some of these have been sandblasted and coated for exposure and aesthetic effect. The resulting bending angles were collected and analyzed by Analysis of Mean (ANOM), Analysis of Variance (ANOVA) and Interactions Plots (IP) and 3D maps of the bending angles according to the most significant operational parameters were also plotted. The obtained results demonstrate the feasibility and flexibility of the technology to generate different shapes. In conclusion, laser forming was found to be a promising forming technology, being it suitable to generate arbitrary 3D forms through the implementation of tailored laser scanning paths and appropriate settings of the operational parameters.