Systematic Repeatability Analysis of Nanosecond Pulsed Laser Texturing

The fabrication of specific surface features requires an adequate level of repeatability to be applied in industrial production environments. Although reference is frequently made to repeatability as a strength of many micro-machining techniques, few works in the literature have been dedicated to systematic and quantitative study of this parameter. The purpose of this work was therefore to quantitatively analyze the repeatability of textured surfaces with an original approach. Aluminum alloy substrates were textured with nanosecond laser pulses to produce micro-dimple arrays. Such features are widely employed to enhance wettability and tribological behavior, for which analysis was performed in terms of interfacial area and void volume. To give the work a more general character, two other parameters based on the definition of the Pearson’s Correlation Coefficient were also tested and compared to find the most suitable parameter for assessing repeatability for a given application. Finally, a study of the point-to-point repeatability of single surface features was conducted to detect variations in process repeatability in different portions of the same processed area. For the specific laser texturing process considered, it was found that an increase in total energy dose led to improved process repeatability.