Laser surface texturing (LST) is one of the most promising technologies for controllable surface structuring and the acquisition of specific physical surface properties needed in functional surfaces. The quality and processing rate of the laser surface texturing strongly depend on the correct choice of a scanning strategy. In this paper, a comparative review of the classical and recently developed scanning strategies of laser surface texturing is presented. The main attention is paid to maximal processing rate, precision and existing physical limitations. Possible ways of further development of the laser scanning strategies are proposed.

A shifted laser surface texturing method (sLST) was developed for the improvement of the production speed of functional surface textures to enable their industrial applicability. This paper compares the shifted method to classic methods using a practical texturing example, with a focus on delivering the highest processing speed. The accuracy of the texture is assessed by size and circularity measurements with the use of LabIR paint and by a depth profile measurement using a contact surface profiler. The heat accumulation temperature increase and laser usage efficiency were also calculated. The classic methods (path filling and hatch) performed well (deviation ≤ 5%) up to a certain scanning speed (0.15 and 0.7 m/s). For the shifted method, no scanning speed limit was identified within the maximum of the system (8 m/s). The depth profile shapes showed similar deviations (6% to 10%) for all methods. The shifted method in its burst variant achieved the highest processing speed (11 times faster, 146 mm²/min). The shifted method in its path filling variant achieved the highest processing efficiency per needed laser power (64 mm²/(min·W)), lowest heat accumulation temperature increase (3 K) and highest laser usage efficiency (99%). The advantages of the combination of the shifted method with GHz burst machining and the multispot approach were described.

Laser surface texturing is a promising technology for future wide applications of functional surfaces with specific properties like hydrophobic, antibacterial, adhesive, self-cleaning, anticorrosion, light absorbing, low friction, etc. Great advancements have been made in this field in the last few years, but in most cases, it takes from minutes up to 1 h to produce 1 cm2 of a functional surface. Even the availability of high-power ultrashort pulsed lasers in the last few years did not dramatically increase productivity, because there are physical limitations of current processing methods: heat accumulation and oxidation, plasma shielding effect, and precision at high speeds. In order to solve these limitations, there have been developed a new method called a shifted laser surface texturing (sLST) method. The new method has a potential to be at least 100 times more productive with no heat accumulation effect and virtually unlimited number of complex shape objects produced with high precision on the surface. In the present work, the principle and advantages of the method are described. The results of the method are compared with two standard methods (path filling of objects and hatch over all objects). The sLST method is presented in both single pulse and burst variants. Examples of its application on different materials for increased adhesion of surface coatings are shown.

Laser scanning processing of nickel-based superalloy AM1 surfaces by ultra-short pulses (10 ps) is introduced as a cleaning and deoxidation postprocess. The laser cleaning is investigated with two-directional surface scanning by a laser beam with several frequencies of pulse generation. The EDX elemental analyses of the laser cleaned AM1 surfaces were compared with the non-laser treated surface. The optimal speed, laser pulse repetition frequency, overlapping and layer repetition count are determined for minimal structural changes on the mechanically polished AM1 surfaces. The laser cleaning after shifted laser surface texturing (sLST) is presented as a two-step preparation of a superalloy surface for thermal spraying. The heat accumulation effect and temperature fields are calculated from a semi-planar model of a laser beam scanning heat source. The theoretical results are discussed in comparison with experimental studies. The upper and bottom bounds are defined for an optimal high speed laser cleaning process

The preparation of surfaces for coating processes is indispensable for maximal adhesion and good coating results. These technical surfaces can be treated by chemical, mechanical, or physical procedures. In thermal spray coating, grit blasting is a standard process for surface preparation. This mechanical roughening and activation of the surfaces is fast and easy to handle. On the negative side, the grit gets wasted and the generated pattern is inflexible. Therefore, attempts to substitute grit blasting with a laser application is discussed in this article. Herein, a theoretical evaluation of high‐speed laser surface texturing (LST) is performed to find limits and points for the optimization of these processes. To estimate the surface processing rates, continuous wave, nanosecond, and ultrashort pulse laser machined dimples and grooves are investigated, and results of the spray coatings are presented afterward. The steel substrates are coated with Stellite 6 and tungsten. Adhesion tests and coating structures are analyzed. In terms of the optimization of the laser texturing, in situ temperature measurements show the influence of the laser process speed on the thermal load of the substrate. The influence of the number of scanning repetitions on heat accumulation during LST is also analyzed.