# Research on Basic Properties of Polymers for Fused Deposition Modelling Technology
###### Abstract  
This study investigates the mechanical properties and biocompatibility of eight commercially available filaments tailored for Fused Deposition Modeling (FDM) additive manufacturing. Test specimens were fabricated using original PRUSA MK4 printers, with ten samples from each selected polymer. Mechanical evaluations through static tensile and three-point bending tests revealed that PETG Carbon and PA+15 CF exhibited superior tensile and flexural strengths, making them highly suitable for applications requiring high mechanical resilience. biocompatibility assessments in line with the ISO 10993-5:2009 and ISO 10993-12:2021 standards indicated that all materials except FiberFlex 40D Fiberlogy were non-cytotoxic, supporting their potential in biomedical applications. The experimental data established material constants within the Johnson-Cook strength model, which effectively predicted the mechanical behaviors of monotonic materials like FiberFlex 40D, PETG, HIPS, TPU, and PA+15 CF Rosa 3D, with maximum fitting errors not exceeding 2.6%. However, the model was inadequate for non-monotonic materials like PLA and PETG, resulting in higher errors and less accurate simulations. Scanning electron microscope (SEM) analyses provided insights into fracture mechanisms, correlating fracture surface characteristics with mechanical performance. This comprehensive study advances the understanding of mechanical properties in thermoplastic materials for 3D printing, validates numerical models for certain materials, and confirms material suitability for biomedical use. FDM; SEM analysis; mechanical properties; additive manufacturing; three-point bending 2024 anatomical structure for preoperative planning, for instance, is crucial in many medical contexts [10; 11]. Additionally, objects fabricated with FDM that are intended for external use, such as prostheses, rehabilitation devices, and medical equipment, can be customized in ways that significantly enhance their functionality and fit. Moreover, the flexibility of FDM technology to incorporate various materials--ranging from carbon fiber-reinforced polymers to flexible filaments such as rubbers and silicones--broadens its applicability. The precision of the FDM technique is often sufficient for external medical applications, and the technology's ease of manufacture, low cost, and availability allow for the rapid production and distribution of these elements, particularly in scenarios where access to medical facilities may be limited or where a temporary solution is necessary. Despite these strengths, FDM technology also has its limitations. A significant drawback is the restricted range of compatible materials, which can limit the applicability of FDM for biomedical implants and other internal applications. While external applications may tolerate the current level of precision, internal applications often require additional post-processing steps to meet the stringent accuracy and reliability standards expected within the body. Nonetheless, the technology is advancing rapidly, and recent developments show promise in addressing these limitations, especially through enhancements in material properties and printing precision [12; 13; 14]. Given the evolving landscape of FDM technology, it is crucial to evaluate both the mechanical and biological properties of the materials used in these additive manufacturing processes. Over the past decade, extensive studies have been conducted to assess the impact of the FDM process on material properties, as well as the behavior of various filaments under different conditions [15; 16; 17; 18; 19; 20; 21; 22; 23]. [PERSON] [24], for example, demonstrated how variables such as the printing orientation and material thickness impact mechanical properties, identifying the optimal printing orientation for enhanced predictability in material behavior during strength testing. Similarly, [PERSON] [25] examined the basic mechanical characteristics of PLA and ABS filaments, yielding valuable insights into their tensile strength and elastic modulus.