The most common types of plastic used for FDM 3D printing are PLA and ABS.

PLA stands for Polylactic Acid or Polylactide, which is plant starch based.
ABS stands for Acrylonitrile Butadiene Styrene, which is petroleum based.

Both thermoplastics have their own specifics with respect to impact strength, density and melting temperatures.  This means it is up to the user to decide which thermoplastic is best suited for the 3D design.

PLA

PLA is a thermoplastic which is extruded from the starch of plants, such as corn, cassava, sugarcane, cereals, or sugar beet.  By being derived from biological resources this type of thermoplastic can be biodegradable under the right conditions.  Biodegradable means that it can be broken down over time through a process involving microorganisms (fungi or bacteria).

ABS

ABS is a thermoplastic which is produced by the polymerization of acrylonitrile, butadiene, and styrene.  ABS is produced from fossil fuels, meaning that it is not biodegradable and has a greater environmental impact than PLA.  Also it is not safe to use for products which may come into contact with food.  ABS requires higher temperatures to extrude than PLA.

 

COMPARISON

ABS 

PLA

Impact resistant and tough Impact resistant and tough
Hard More brittle than ABS
Glossy Can droop if it gets too hot
Flammable
Usually bends before it breaks
Strong, toxic smell when it is being printed
Strength is relatively equal to PLA
Turns white along the high stress zone when it is bent; may break into little pieces
Sweet scent when being printed
Strength is relatively equal to ABS
Prone to cracking if cooled too quickly

 

 

ENVIRONMENT

Please keep in mind that PLA has less environmental impact and therefore, whenever the situation occurs that either thermoplastic specifications are suitable for your design, PLA is recommended as the most sustainable option.