Plastics

Plastics can be divided into two categories based on their behavior at high temperatures.

Thermoplastics can be melted, cooled, and solidified multiple times. However, the material properties of thermoplastics degrade with each melt/cool/solidify cycle. The degree of degradation depends on the material used, so if the material properties need to be preserved, fresh material must be added to the mix. Commonly used PLA filaments can be recycled about 3–5 times before their material properties significantly deteriorate. For powder materials, the commonly used polyamide 12 (nylon) requires 20–40% fresh material to be added after each print cycle.

Thermoset polymers form covalent bonds during manufacturing, which prevents the plastic from melting and being reprocessed. Photopolymers are thermosets that use light to initiate the polymerization process.

Thermoplastics (filaments and granules)

For Material Extrusion method there are hundreds of different thermoplastics and various composites available in both in filament and in granule forms.

PLA (Polylactic Acid): The most commonly used material in consumer-level 3D printing. It is a biodegradable thermoplastic made from renewable raw materials such as corn starch or sugarcane.

ABS (Acrylonitrile Butadiene Acrylate): One of the most common printing materials, known for its good durability and hardness.

ASA (Acrylonitrile Styrene Acrylate): Developed as an alternative to ABS with slightly better weather resistance.

HIPS (High Impact Polystyrene): A technical material developed alongside or as a replacement for ABS.

PVA (Polyvinyl Alcohol): A water-soluble material typically used as a support material in 3D printing.

PETG (Polyethylene Terephthalate, Glycol-modified): A common 3D printing material that combines PLA’s ease of printing with ABS’s technical properties.

TPU (Thermoplastic Polyurethane): Likely the most common flexible printing material used in material extrusion. It has good wear resistance and chemical resistance.

PEEK (Polyether Ether Ketone): A specialty plastic considered one of the best technical plastics in terms of properties. However, it requires a nozzle temperature over 400 °C, a heated chamber, and precise control of the printing process.