Investigation of the Printing Parameters Influence on the Bond Lines Length in Fused Filament Fabrication

The study results of the cross sectional profile geometry of extruded strand in fused filament fabrication (FFF) were presented. It was obtained that the plane characterized by the shortest time of deposition of two layers represented the longest contact lines between them. It was established that the length of contact line between the layers was different in the early and late stages of deposition. The length of the lines was influenced by heat transfer between adjacent strands. The length of the intra-layer lines increased with increasing printing speed due to the acceleration of diffusion processes from additional heating during deposition of the next layer. The rational printing speed was 20 mm/s. The relationship between the accuracy of printed layer and value of extrusion multiplier was established. As it increased, porosity of layer decreased, but the accuracy of material deposition significantly deteriorated. The rational value of extrusion multiplier was 1, in this case minimum porosity was obtained with sufficient printing accuracy.