Influence of femtosecond laser pulse sequence on the morphology and roughness of titanium surface micro-patterns

Abstract

The geometry of the medical titanium surface micro pattern, the micro- and nanostructures within the pattern, and the roughness of the structure are key parameters affecting the integration of the implant surface with the bone tissue. The femtosecond laser is an effective method for surface modification of implants, but achieving effective control of the depth of the pattern and the inner surface topography and roughness is a crucial processing challenge. In this study, the evolution of ablation pit morphology with process parameters was analyzed to establish the correspondence between process parameters and the ablation mechanism. A femtosecond laser pulse sequence method is proposed to increase the machining depth from 24 μm to 38 μm while reducing the surface roughness from Sa = 2.2 μm to Sa = 0.5 μm by regulating the liquid phase migration as well as the thermal phase change process without affecting the processing efficiency. And the surface roughness can be reduced from Sa = 2.2 μm to <0.1 μm with appropriate pulse sequence parameters.