Characterization of the mesostructure of fused-deposition acrylonitrile-butadiene-styrene materials

Fused-deposition (FD) is a robotically controlled "fiber" extrusion process that produces a new class of materials with a variety of controllable mesostructural features related to fiber layout and the presence of voids. Mesostructural features of importance to the stiffness and strength of unidirectionally extruded materials were characterized as a function of the processing variables. Samples were made using the Stratasys FDM1600 Modeler with the P400 acrylonitrile-butacliene-styrene plastic. Results showed that the void geometry/density and the extent of bonding between contiguous fibers depended strongly on the fiber gap and extrusion flow rate. Settings for minimum void and maximum fiber-tofiber bonding were determined. Void and bond length densities in the plane transverse to the fiber extrusion direction varied from 4 to 16 per cent and 39 to 73 per cent respectively. The results quantify the important mesostructural features as a function of the FD process variables and are expected to find use with other FD materials.