THE INFLUENCE OF ANNEALING TEMPERATURE ON TENSILE STRENGTH OF POLYLACTIC ACID

Polylactic acid is one of the most used materials in Additive Manufacturing technologies, especially in Fused Filament Fabrication. Although its tensile strength is relatively good in comparison with other materials in the same price category, it is possible to increase it after printing by annealing. One of the most important parameters for annealing is the annealing temperature. This article deals with experimental testing of the influence of annealing temperature on tensile strength and change of dimensions of polylactic acid samples produced by Fused Filament Fabrication. Three different variations of polylactic acid material were used for testing. The samples were annealed at 60, 80, 100, 120, 140 and 160 degrees C for 30 minutes and then after gradual cooling in air, they were remeasured to determine their deformation. All the annealed samples and a set of nonannealed samples were subjected to a tensile test. Compared to the nonannealed samples, all annealed ones changed their tensile strength depending on the annealed temperature. Also, a dependence of the annealing temperature on the dimension change was found.