## 2 Literature Review  
Given the topicality of the addressed issue, the following chapter describes ongoing or already conducted research. This research delineates various approaches concerning the adhesive properties of print beds and materials for FFF manufacturing. It is imperative to highlight the relevance of the research topic in the introduction. [PERSON] et al. studied the adhesion of the initial layers of printed models produced using FFF technology on a textile substrate [4]. To assess this adhesion, they introduced three testing methods: perpendicular tensile testing, shear testing, and peel testing, applied to six different textile substrates. For printing, Polylactic Acid (PLA) filament was selected, and the objects were fabricated on a textile base affixed to the printer bed. The study's contribution lies in identifying that the most suitable method for testing the adhesion of the initial model layer is the perpendicular tensile test, presenting a lower risk of tearing the textile substrate. [PERSON] et al. presented research on warping deformations of printed models using FFF technology [5]. Laser scanning was utilized for deformation measurements and comparison against the nominal model. Epoxy adhesive was applied to the print bed to enhance the adhesion of the initial layer. It was observed that, when using PLA material, deformations have a reduced impact on the manufactured model. They underscored the necessity of using a heated bed, particularly when printing ABS material, emphasizing the importance of proper printing conditions for the initial layer's adhesion and its influence on overall deformations and detachment of the resulting print. However, despite measuring model deformations with a laser scanner, the study did not directly investigate the adhesion of the initial layer. [PERSON] et al. focused on improving the adhesion of the initial layer in 3D-printed models produced by FFF technology [6]. They investigated the influence of different print bed temperatures when printing PLA and Acrylonitrile Butadiene Styrene (ABS) materials using multiple print bed types. It was discovered that print bed temperature significantly affects the initial layer's adhesion, with higher temperatures enhancing adhesion. They recommend utilizing a print bed heated slightly above the glass temperature of the filament. Additionally, they proposed a custom-designed shear-off force testing device for assessing the initial layer's adhesion. This device tested the shear-off force acting on the printed model in a parallel direction to the printed layers but did not study the adhesive properties of the initial layer perpendicular to the print bed. [PERSON] examined the adhesive properties of 3D-printed models using FFF technology on a print bed with the application of tapes [7]. For measuring the adhesive forces of the initial layer on the bed, an experimental device was proposed, focusing on force measurements perpendicular to the print bed. The contribution of the study lies in the design proposal of an experimental testing device and the validation of its functionality. [PERSON] et al. studied the adhesive forces of printed models and the influence of print bed temperature with borosilicate glass and polyamide surface materials [8]. They designed a testing device to measure these adhesive forces. Within this device, measurements were conducted parallel to the printed layers, highlighting the potential use of applying and measuring force magnitude on the manufactured part, unlike pulling the part from the print bed. [PERSON] et al. conducted research on the adhesive properties during printing between PLA and Thermoplastic Polyurethane (TPU) materials [9]. The focus of this research was on testing the influence of process parameters on the mutual adhesion of these materials, utilizing shear tests for measuring these forces. It was found that inadequately chosen process parameters affect layer adhesion, potentially causing unsuccessful printing. [PERSON] et al.