“In developing a laser process for an application, the knowledge and the appropriate hardware to apply the laser radiation to the material that we want to process are indispensable”.

In developing a laser process for an application, one of the essential requirements is to have an appropriate laser source. But at the same time, the knowledge and the appropriate hardware to apply the laser radiation to the material that we want to process are indispensable. That is why the Multipoint project contemplates these two activities in parallel: the development of a femtosecond laser source and the design of heads adapted to the requirements of the application.

Previous experiences with less powerful lasers, but working with femtosecond pulse regimes, help us to determine the main characteristics of the application for the drilling of titanium plates. In turn, these characteristics provide us with data for the design of laser heads and multibeam generators. This is the usual development strategy for any laser material processing. However, this strategy would be much more effective if, while we investigate the development of the process, the knowledge acquired is also used to provide clues about its measurable characteristics. This would allow us to monitor the process first and later develop control strategies in case we observe deviations from optimal conditions. This is the overall strategy contemplated in the Multipoint project. In fact, we can determine on a small scale what are all the optimal parameters to drill holes in Ti at a certain rate. But, can we ensure that no deviation will occur when producing drilled sheets with millions of holes? The answer is obviously no, and that is why monitoring and control strategies also play a relevant role in the project.

Not only in-situ monitoring techniques are being applied, that is, techniques that allow us to measure aspects of the drilling process while it is being carried out. Moreover, we’ll use off-line methods that can be implemented in future production processes to provide immediate measurements of the characteristics of the micro-holes. Therefore, we will not only be able to make millions of holes, but also to have each of these holes characterized.

The correlation of in-situ and off-line measurements provides unique information on the potential issues that can appear in the production of these plates. As well as elements of the laser process that can go unnoticed when only a few holes are produced. In the Multipoint project, we have shown that the development of the laser process and all the hardware that is needed is not enough. Monitoring and control are essential as well.