Rheological and printable behavior of resin - class materials for 3D printing applications

Purpose This study aims to investigate rheological and extrusion behavior of thermosetting epoxy resins, which to find the universal property and printing parameters for extrusion-based rapid prototyping applications. Design/methodology/approach The thickener proportion greatly influences its viscosity and rheological behavior and therefore plays an important role in the shape of the cross-section of the extrudate. Findings A pseudoplastic (shear-thinning) is a basic requirement for obtaining extruded lines with plump cross-sections. In addition to the effects of the rheological behavior of the composite, shape maintenance and its wettability on the substrate, the cross-sectional geometry of the extrudate is also strongly affected by printing process parameters including the extrusion nozzle height, nozzle moving speed, extrusion rate and critical nozzle height. Proper combinations of these process parameters are necessary to obtain single-line extrudates with plump cross-sections and 3-D objects with dimensional accuracy, uniform wall thickness, good wall uprightness and no wall slumping. Formulas and procedures for determining these extrusion parameters are proposed and demonstrated in experiments. Originality/value The results obtained have been explained in terms of the interactions among the rheological properties of the composite, the shear rate imposed on the composite during extrusion, the wettability of the composite on the substrate and the shape maintenance of the composite during extrusion.