## 1 Introduction
However, they do not explain the effect or importance of sample preparation. In mechanical and material engineering, the use of laser radiation depends on many factors, primarily the properties of the materials being processed. Lasers are widely used in industry for surface treatment, marking products by engraving, precise cutting, and welding. There are also many subcategories of these processes, such as welding, cutting, surfacing, alloying, soldering, and laser micromachining, which includes microdrilling, microsurfacing, microwelding, engraving, ablative cleaning, and surface texturing. An exemplary division of mechanisms for laser modification of the surface layer was proposed by [PERSON] et al. [2]. The use of lasers in industry allows for improvements in efficiency and production speed while maintaining high precision, high quality, and repeatability of the process. An additional advantage is a clean workstation and the lack of waste materials during the machining process [2; 11; 12]. Material engraving with a laser beam can be used to mark the product, obtain specific visual and decorative effects, or modify the surface layer of a given material. Laser ablation involves the removal of material through the process of evaporation of surface layer material. Laser ablation is most often performed with short-pulse lasers, but depending on the power of the laser beam, the process can also be performed using lasers for continuous operation [12]. Performing laser modification to the surface layer both changes the composition of the alloy and gives it different microstructural features, but only on the surface of the material, which often results in improved resistance to corrosion and the formation of fatigue cracks [6; 22]. When using a laser beam to modify the surface layer, special attention should be paid to the surface preparation process [7; 20]. In the case of engraving, maximizing the efficiency and repeatability of the process is the key to obtaining the desired properties. Engraving a shiny metal surface can lead to laser beam dispersion and energy loss. Some materials require special preparation and surface darkening in order to be effectively engraved [18; 23]. The purpose of the conducted research was to select a suitable method for modifying the surface layer of AISI 316L stainless steel. AISI 316 is the second most commonly used stainless steel grade in the industry. The 316L version is a low-carbon variant of the 316 alloy, which makes the 316L stainless steel suitable for welding, which is especially important in the case of laser processing [24; 25; 26]. Due to the lack of detail about sample preparation in the literature and very little data about laser parameters such as power, frequency, pulse application time or speed, it seems to be very difficult for young researchers to decide on good starting parameters. The authors also noticed a lack of failure test descriptions. Since it is commonly stated that \"one develops success from failures\" and \"discouragement and failure are two of the surest stepping stones to success\", the authors find it important to share both successful aspects of the study along with the failure-full path that precedes success. However, constantly starting the experiment from scratch and repeating the trial-and-error method lead to an immense waste of materials and energy. This waste could be avoided by simply sharing the knowledge of best practices and those that are usually classified as proper. Thin (<5 mm) AISI 316L samples were subjected to laser texturing using different laser beam parameters. Then, they were experimentally scrutinized to see how much a proper sample preparation procedure affects the final result of the modification. The obtained effects were subjected to verification and microscopic observations, thus eliminating modifications that did not meet the objectives of the experiment.