# Tribological Analysis of Fused Filament Fabrication PETG Parts Coated with IGUS
The basic materials within FFF are ABS (acrylonitrile butadiene styrene) and mainly PLA (polylactic acid) for its ease of manufacture [16]. These materials have shown that ABS parts have better tribological properties compared to PLA. Additionally, adding carbon fibers to PLA has shown improvements in wear resistance and reduced friction coefficient [17]. However, other materials like PETG (polyethylene terephthalate glycol) offer excellent tribological performance [10]. This material is highly resistant to impacts and chemicals, making it an ideal tool for use in industrial environments. PETG is also known for its excellent layer adhesion during the printing process, allowing for the fabrication of parts with high structural integrity and wear resistance. Furthermore, its recyclability and low moisture absorption make it a sustainable and practical material for various applications. Compared to PLA and ABS, despite these materials having high strength [18; 19], PETG has a higher load capacity and elongation [20; 21]. Additionally, although PLA is a biodegradable material, PETG is easily reusable. Moreover, there are other special materials, like those developed by IGUS for better tribological performance. IGUS materials are used in components that must withstand continuous movement, such as bearings, linear guides, and gears. IGUS tribological filaments are formulated with self-lubricating polymers that significantly reduce the need for maintenance, improve efficiency, and prolong the life of printed parts. Among their products in this field are filaments for FFF designed to operate without additional lubrication that offer excellent wear resistance, even under adverse conditions [22]. Using these materials in the FFF process not only facilitates the creation of customised parts but also allows for superior tribological characteristics. IGUS filaments can be used as easily as other thermoplastics but offer the additional advantage of improving the friction and wear properties of the resulting parts [22]. This is particularly useful in applications where components are subject to constant movement and mechanical loads, such as in the automotive, aerospace, and machinery manufacturing industries [23; 24]. This ability to use advanced materials significantly expands the scope and functionality of parts manufactured with FFF, providing effective and durable solutions for a wide range of mechanical and structural applications. There is even the possibility of creating parts with dissimilar materials, which opens a new frontier in the use of FFF, taking advantage of an advantage that so far was only used to create support structures. Multi-material manufacturing enables the creation of parts that combine various properties in a single object, optimising mechanical performance and expanding design and functionality capabilities. This approach allows for the designing of components that leverage the unique characteristics of various materials to improve efficiency and durability [25; 26; 27]. Thus, it would be possible to create parts with mechanical performance optimised for their final application, even if it is a tribological application. However, this possibility is not yet industrially implemented. Upon analysing this information, it is found that there are fewer studies related to the tribological behaviour of parts manufactured with FFF compared to other mechanical properties, such as tensile or compression, so much so that there is no established procedure for the characterisation of tribological behaviour due to the influence of a large number of involved parameters. This lack of knowledge is even more pronounced in more novel or specific materials. Additionally, there are no previous studies that analyse parts manufactured with different materials, dissimilar materials, or coated materials. One of the great advantages of additive manufacturing is the ability to offer different properties to different zones of the parts depending on the material deposition and the type of material deposited.