Assessing roughness of extrusion printed soft materials using a semi-quantitative method

Abstract Extrusion printing with hydrogel materials is the most widely employed bioprinting method at present. The smoothness of extruded filaments affects the fidelity of printed structures heavily, which is considered as one of the criteria to evaluate printing quality. A new method via introducing a semi-quantitatively dimensionless number (Roughness Number) is presented in this paper to better quantify the smoothness of extrudates in hydrogel printing via extrusion. The main indices affecting the roughness of the printed filaments are evaluated, including nozzle geometry, translational speed, nozzle-platform gap, pneumatic pressure, etc. The proposed paper guides the subsequent synthesis of new biomaterials and establishes a potential framework for the quality evaluation of extrusion 3D printing.