ABS, which stands for "Acrylonitrile Butadiene Styrene", is a type of plastic material in the form of a string, referred to as filament, which is used in 3D printers working on the principle of FDM, i.e. the gradual deposition of molten material. It is characterised by its high mechanical strength, toughness and ability to withstand higher temperatures and impact compared to the more common PLA material. These properties make it suitable for the production of functional prototypes, stressed mechanical parts such as gears or brackets, and enclosures for electronics. A well-known example of an ABS product is Lego bricks. Printing from ABS requires specific conditions. A higher print nozzle temperature is required, as well as a heated print pad. The heated pad prevents an undesirable phenomenon called "warping", in which the model shrinks due to cooling and its corners come off the pad. For reliable results, it is recommended to print in a closed print chamber, which maintains a stable ambient air temperature and protects the print from drafts, thus reducing the risk of cracking between layers. During melting, ABS releases fumes with a characteristic smell, so it is necessary to ensure good ventilation of the room where the printer is working. Finished prints can be easily machined, for example sanded, drilled or glued. A specific feature of ABS is the possibility of chemically smoothing the surface with acetone vapour, which seals the visible lines between the print layers.