Comparison of mechanical properties in FDM additive manufacturing and compression molding of polylactic acid (PLA)

Polylactic acid is one of the most popular polymers for ۳D printing using the FDM method. Layer-bylayerconstruction in ۳D printing results in different mechanical properties depending on the directionof printing and usually lower properties compared to other materials manufacturing methods. In thisregard, to compensate for the loss of mechanical properties, solutions such as the use of reinforcingmaterial or heat treatment have been proposed. However, the amount of deterioration in mechanicalproperties in ۳D printing is still significant. The ۳D printing method was compared with compressionmolding and changes in mechanical properties were investigated in these two methods. In the tensiletest, samples made by the FDM method had better mechanical properties, and roughly ۱۳ percent highertensile strength than samples made by compression molding. According to the results, the compressionmolding method was the preferred method for making the samples in the bending and impact test dueto the higher performance of these samples. Impact and flexural strength of compression moldedsamples were roughly ۲۰۰ percent and ۸۰ percent higher respectively. The deficiency of FDM is dueto its layer-by-layer construction, and the disadvantage of compression molding is the possibility ofvoids in this manufacturing method.