Compensation of structure distortion in nonisothermal hot forming of laser structured thin glass

Modern automotive industry employs a variety of complex shaped glass components, from touchscreen displays, dashboard screens, weather resistant windshields to tinted sunroofs. Currently around 50% of these components are functionalised by adding microstructures in a process based on etching or replication processes with structured forming tools, which are neither environmentally nor economically friendly. We present a new approach to functionalise such surfaces by direct laser structuring of glass substrates, thereby reducing costs and energy consumption by up to 60% and avoiding harmful chemicals compared to conventional processes. Current developments in high-power laser-beam sources and laser system technology enable low cycle time direct structuring of glass substrates. Laser-based direct structuring can generate a large portfolio of functional structures of different sizes which we showcase in haptic, hydrophobic and anti-glare structures. The downstream forming of structured glass interferes with high demands of the automotive industry due to shape distortions and positional distortions of the structure. Therefore, we developed a FEM-based predistortion method to adjust the laser trajectory, compensating for the influence of 2D glass moulded into a 3D shaped product. The compensation method was validated by conducting hot forming experiments with different laser-induced geometries on one-dimensional curved forming tools. We were able to reduce the distortion error by more than 90%.