Highly-dense acrylonitrile butadiene styrene specimens fabricated by overheat material extrusion 3D printing

Purpose This study aims to comprehensively investigate the process-structure-property correlation of acrylonitrile butadiene styrene (ABS) parts manufactured by the overheat material extrusion (Mex) method. This study considers the relationships between the tensile and impact strength with temperature profiles, mesostructures and fracture behaviors of the ABS-printed parts. Design/methodology/approach The overheat printing condition was generated by using the highest possible printing temperature of the Mex printer used in this study together with cooling fan turned off. Temperature profiles of the polymer rasters were measured to characterize the diffusion time of the deposited rasters. Thermogravimetric analysis, differential scanning calorimetry and melt flow index were performed to study the thermal properties of the ABS feedstock. The mesostructures of the printed ABS samples were characterized by using an optical microscope, while their fracture surface was investigated using a field emission scanning electron microscope. The authors performed the tensile and impact tests following ASTM D3039 and D256-10A, respectively. Findings The use of the overheat Mex printing could offer better raster diffusion with reduced cooling rate and prolonged diffusion time. Consequently, the overheat printed ABS parts possessed a porosity as low as 1.35% with an increase in the weld length formed between the adjacent rasters of up to 62.5%. More importantly, the overheat printed ABS parts exhibited an increase of up to 70%, 84% and 30% in tensile strain at break, tensile toughness and impact strength, respectively, compared to their normal printed counterparts. Originality/value This study provides a facile but effective approach to fabricate highly dense and strong polymeric parts printed by Mex method for end-use applications.