Comparing the adhesion strength of 316L stainless steel joints after laser surface texturing by CO2 and fiber lasers

This paper focuses on the effects of the laser surface texturing process and joint configuration of stainless steel adherends on the adhesive tensile bond strength. Two different sources, a CO2 and a fiber laser, were used and compared. In particular, proper choice of laser parameters was explored with the aim of producing different roughness and peak-to-valley distance and different textures on the bonding area, which could increase the real contact surface. Furthermore, to more thoroughly understand the effect of the laser parameters on joint fracture load, the experimental campaign was conducted according to a Design of Experiment (DoE) framework and the results were analyzed with this methodology. The creation of particular textures and roughness levels were related to the resulting joint geometrical configuration and bond strengths. In particular, significant increases in joint bond strength were achieved using both laser sources. Furthermore, by optimizing the laser parameters, smaller laser spot scan path overlaps can be achieved as well as a more refined scale of surface texture and surface roughness. This thereby enables the joining of thinner sections of different materials.