Laser surface texturing for the improvement of press-fit joint bond strength

Abstract

The laser surface texturing has been developed for a number of applications including for enhancing the tribological properties of structural components and for improved interference fit joints. In this study, the relationship between the micro-surface textures properties and surface texture dimensions of the material such as diameter increase were determined. Optimum levels of laser power, focal position and scanning speed of the part during processing were determined. The study involved theoretical and experimental analysis of the surface response of the press-fit parts to determine optimum parameters and their corresponding changes for high joint strength and lifetime of the joint. Due to the centrifugal force, the assist gas ejection and the overlapping laser scanning tracks, the re-solidified molten surface creates a pre-defined surface texture on the material. The laser surface texturing of the interference fit pins produced an interference percentage from 4.8% to 71.4% which corresponded to insertion pin diameters from 10.2mm to 18mm. The experiments showed that the parameters had a direct correlation with joint strength with values recorded between 6.84MPa to 184MPa. The analysis showed the ability to control the tensile strength of the joint structures. The experiment work performed provided a map of the relationship between the process parameters, the surface texture width and height, and the joint strengths.