Fabrication of bone scaffolds by additive manufacturing of fused deposition modeling (FDM) and investigation of their mechanical properties

The use of Additive Manufacturing (AM) techniques in medical science has resulted in a great change in this field, especially in bone tissue engineering. One of these techniques is the Fused Deposition Modeling (FDM) which is used to make bone scaffolds. From view point of bone tissue engineering, bone scaffolds must have acceptable mechanical properties in addition to the required biological properties. In this study, at first the printing parameters including layer height, printing speed and number of filaments in each row were determined and bone scaffolds were made with two different materials polylactic acid (PLA) and polycaprolactone (PCL) and were subjected to the compression tests. The results of Young’s modulus and yield stress analyzed in Design Expert software showed that increasing the layer height reduces the mechanical properties. Also, increasing the number of filaments in each row increases the elastic modulus of the scaffold. For example, for scaffolds made of PLA, the maximum modulus of elasticity belongs to 12 filament scaffolds with a layer height of 0.1, which is equal to 319 MPa, and the minimum elastic modulus belongs to 8 filament scaffolds with a layer height of 0.3, which is equal to 143 MPa. Printing speed for scaffolds made of PLA does not have a significant effect on the Young’s modulus and yield stress. But for scaffolds made of PCL, increasing the printing speed reduces the modulus of elasticity but it doesn’t have a significant effect on yield stress.