Conference Agenda

Direct Laser Interference Pattering (DLIP) has evolved as an efficient method for surface functionalization by producing periodic structures. When using femtosecond or picosecond laser sources, the produced topographies are also covered by Laser Induced Periodic Surface Structures (LIPSS), being its orientation controlled by the polarization direction of the beam. On the other hand, the orientation of the LIPSS has an effect not only on the geometry of the produced patterns, but also in the ablation efficiency during the structuring process. In this work, stainless steel 304 and aluminum 2024 plates are treated with 12 ps and 70 ps laser pulses (1064 nm) using DLIP, producing line-like structures with 6.0 µm and 5.4 µm periods when rotating the polarization direction and thus the LIPSS orientation. It was found that the ablation efficiency can be improved significantly when the LIPSS are perpendicular to the DLIP features.

The characterization of laser-textured periodic surface topographies, such as Laser-Induced Periodic Surface Structures (LIPSS) and Direct Laser Interference Patterning (DLIP), plays a key role in the advancement of material functionalities in various industries. In this work, we present an innovative FFT-based device that uses diffractive methods for accurate real-time analysis of complex surface patterns. This non-invasive and scalable approach is adaptable to different substrates and pattern types and offers a significant improvement in quality control over traditional techniques. By integrating Fourier transform analysis with diffraction-based measurements, the device provides an accurate determination of spatial frequencies, periodicity, and deviations in surface textures, critical parameters for optimizing laser fabrication processes. Experimental validation confirms the device reliability in characterizing LIPSS and DLIP structures and demonstrates its potential for practical integration into industrial laser-based manufacturing systems.

Laser Surface Texturing (LST) has emerged as a powerful solution to provide materials with specific functionalities. By creating surface textures and patterns, tailored surface properties can be achieved for distinct applications such as controlling of wettability and optical properties. To boost the implementation of LST at industrial scale, we have investigated the use of a high-power ultrashort pulse laser (USPL) combined with advanced beam shaping technologies as a robust, high quality and highly productive solution for generating functional patterns on different materials.

In particular, we present the laser surface functionalization of both plastic and metallic components for industrial applications. For example, the laser surface texturing of steel inserts for plastic moulding, decreasing the wettability of the material and obtaining hydrophobic properties. In another example, the laser surface texturing of polymer materials, modifying optical properties such as opacity and haze.

There are several challenges when considering surface functionalisation in complex industrial parts. To give an answer to them, BILASURF European Project is developing and integrating a system for high-rate laser functionalization of complex 3D surfaces using tailored designed bio-inspired riblets to reduce friction and improve the environmental footprint of industrial parts, ensuring a high throughput with the help of inline monitoring capabilities. The technology will be demonstrated in hydraulic turbines and industrial fan injection molds, and the integrated system will include two technologies: DLIP (for riblet periods up to 50 µm) and DLW (for riblet periods above 50 µm). Picosecond regime has been used to develop both processes, as the final system will include a single laser source for DLIP and DLW. In the case of the DLW process, an increase of the ablation rate by a factor of four has been achieved using a 1 MHz frequency and burst-mode.

In recent years, surface functionalization through topographical modifications has attracted significant attention for controlling wettability. Among the different technologies available, laser texturing has emerged as a particularly promising technique due to its ability to create micro- and nanometric structures with high precision, repeatability, and automation. However, achieving a specific wettability often requires an iterative trial-and-error approach. This study proposes a methodology to accelerate the selection of the most appropriate texture to control the wetting of polypropylene. This method includes an ultrafast laser parameter optimization process and the identification of the key dimensional factors influencing the contact angle variation through the development of tens of different textures, combined with a CFD Two Phase flow simulation model. By establishing the relationship between texture parameters and wettability, these findings contribute to the rapid development of functional surfaces in polypropylene.

Femtosecond laser processing is an effective technique for modifying polymer surfaces, enabling precise control over topography and chemistry for advanced applications, such as biomedical devices, microfluidic systems, and electronics. This study compares the effects of femtosecond laser irradiation using infrared (IR) and ultraviolet (UV) sources on polymer substrates, focusing on changes in surface wettability and chemical transformations. Surface wettability has been characterized by contact angle measurements, while morphology was analyzed using optical profilometry. IR irradiation induces deeper surface modifications through multiphoton absorption, while UV irradiation results in finer, shallower changes through single-photon absorption. These structural and chemical differences lead to distinct wetting behaviors, depending on whether the polymer is treated with UV or IR laser irradiation. Chemical analysis reveals distinct photochemical pathways activated by each laser source, providing valuable insights for tailoring polymer surface properties.