“Metal 3D printing typically requires high energy laser or electron sources. Recently, 3D printing
using metal filled filaments becomes available which uses PLA filaments filled with metal
powders (such as copper, bronze, brass, and stainless steel). Although there are some studies on
their printability, the detailed study of their sintering and characterizations is still missing.
In this study, the research is focused on 3D printing of bronze filaments. Bronze is a popular
metal for many important uses. The objectives of this research project are to study the optimal
processing conditions (like printer settings, nozzle, and bed temperatures) to print bronze metal
filament, develop the sintering conditions (temperature and duration), and characterization of
the microstructure and mechanical properties of 3D printed specimens to produce strong
specimens.
The thesis includes three components: (1) 3D printing and sintering at selected conditions,
following a design of experiment (DOE) principle; (2) microstructure and compositional
characterizations; and (3) mechanical property characterization. The results show that it is
feasible to print using bronze filaments using a typical FDM machine with optimized printing
settings. XRD spectrums show that there is no effect of sintering temperature on the composition
of the printed parts. SEM images illustrate the porous structure of the printed and sintered parts,
suggesting the need to optimize the process to improve the density. The micro hardness and
three-point bending tests show that the mechanical strengths are highly related to the sintering
conditions. This study provides important information of applying the bronze filament in future
engineering applications.”
Paper published December 2018