This study investigates rheological and extrusion behavior of thermosetting epoxy resins. The purpose is to find the universal property and printing parameters for extrusion based rapid prototyping applications. 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. 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 in order to obtain single line extrudates with plump crosssections and 3D 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.

Keywords: epoxy resins; rheological behavior; printable behavior; 3D printing; extrusion parameters