When processing surfaces with pulsed lasers the precise calculation of all relevant parameters is crucial to ensure repeatable and comparable surface treatments. This lecture describes a novel calculation routine that allows for the precise calculation of parameters like the accumulated fluence on the surface and the total spot overlap. It is shown that currently used methods to calculate the spot overlap oftentimes overestimate the actual overlap by more than 20%. This problem is amplified by irregular spot shapes and the fact that most laser surface treatments that achieve an even surface coverage do so, by hatching multiple scan lines, thus resulting in not only overlap between individual spots but also between scan lines. This makes calculating a total spot overlap more challenging. As a result, it is hard to achieve comparable process parameters when using different laser systems, as well as varying spot diameters or profiles.

This lecture aims to tackle these issues by presenting a set of equations that can easily be implemented in a spreadsheet to accurately calculate all relevant process parameters. To illustrate the approach and its usefulness, two experiments are presented, and all relevant laser parameters are calculated. Afterwards the resulting surfaces are investigated using laser scanning microscopy and image processing to validate the developed calculation routine.