Effect of Extrusion Temperature on Printable Threshold Overhang in Additive Manufacturing

Abstract

Despite of additive manufacturing technologies being rapidly developed with wide applications in the fields of aerospace, engineering, medical application and marine, support structures are still unavoidable for many printed products with overhangs, resulting in extended build time and expensive post-processing, material waste, and sometimes failure to fabricate the part of the required quality. The threshold overhang angle that can be self-supported is generally set at 45° for FDM printers. However, different process parameters such as extrusion temperature and print speed can also have a great impact on printable threshold overhang angle (PTOA). In this paper, the influence of extrusion temperature on PTOA is studied theoretically and experimentally for the achievement of the lowest possible PTOA. First, theoretical analysis of overhang with regard to extrusion temperature is carried out. Then experiments of overhangs with 20°, 30°, 40° and 50° in extrusion temperatures of 175 °C, 190 °C, 205 °C and 220 °C are conducted on an FDM printer. According to the results, PTOA can be quite different under various extrusion temperatures and the theoretical analysis can be used for predicting the lowest PTOA. The findings can also provide some references for future research in high-precision printing by adjusting relevant print parameters.