Additive manufacturing of copper parts using extrusion and sinter-based technology: evaluation of the influence of printing parameters and debinding method

Abstract

PurposeThis work is focused on the realization of copper parts using the material extrusion additive manufacturing debinding and sintering (MEX+D&S) technology.Design/methodology/approachA highly filled filament with 90 Wt.% of copper is used to realize nine different combinations varying the printing speed and the flow rate. The following thermal debinding and sintering are performed at 483 °C and 1057 °C, respectively, burying the samples in specific refractory powder and carbon. The green and sintered density are measured and an inspection at optical microscope is implemented for a detailed internal analysis of the defects.FindingsThe samples, that reported the highest values of the green density, become the worst in the sintered condition due to evident swelling defect generated by the entrapped polymer during the thermal debinding. On the other hand, the parts with the lower values of green density allowed to achieve a satisfying density value without significant external defects.Originality/valueThe realization of copper parts through laser-based additive manufacturing technologies shows several troubles related to the rapid heat transfer and the high reflectivity of copper, which is a hinder of the absorption of the laser power. The MEX+D&S becomes an easier and economical alternative for the realization of copper parts. The internal inspection of the samples revealed the need for the improvement on the process chain, adopting a different debinding process to open channels during the thermal debinding to avoid the entrapment of the polymer.