Increment in laser bending angle by forced bottom cooling

Abstract

Laser bending is extensively used in many applications including shipbuilding, automotive, microelectronics, and aerospace, due to its advantages of non-contact, flexible manufacturing, and ease of automation. However, the low bending angle observed with conventional temperature gradient bending mechanism restricts its wider application. This investigation aims to develop a new methodology to increase the bending angle of temperature gradient-based laser bending process. In this process, an external cooling source was incorporated at the bottom of the plate (co-axial to the laser source), to increase the temperature gradient between the top and the bottom surfaces. A coupled thermo-mechanical model was developed to simulate the process using COMSOL MULTIPHYSICS® and investigate the effects of external cooling source on bending angle. The study reveals that the bending angle and temperature gradient across the plate thickness can be influenced by the external cooling source. Compared to the conventional technique, the use of external cooling source helps to increase the bending angle by around 20%. Moreover, this method yields a significant reduction of HAZ as a secondary benefit. It is also seen that the amount of residual stress increases with increase in cooling source diameters.