“The thermal debinding-sintering process plays an essential role in the context of material
extrusion-based additive manufacturing (AM) for producing parts using metal injection molding
(MIM). During thermal debinding, metal parts often experience material distortion and porosity,
which negatively impacts their mechanical properties. Slowing down the debinding speed is a
common approach to mitigate material distortion and porosity. However, this leads to a significant increase in the debinding time. In this study, we carried out debinding-sintering experiments to optimize the distortion and porosity in metal parts. These metal parts were
manufactured utilizing bronze/polylactide (PLA) blend filaments and placed in crucibles of
different sizes (small, medium, and large), with different heating rates and holding times. The
results revealed that the small crucible yielded higher porosity levels in the metal parts, which
could be reduced from 23% to 12% by extending both the heating and holding times. In contrast,
the medium crucible managed to reduce porosity to approximately 15% without requiring an
extension of the processing time. The large crucible, on the other hand, couldn’t achieve further
porosity reduction due to challenges in reaching the desired temperature. To gain a deeper insight
into temperature distribution during the debinding process, we performed numerical simulations
using the computational fluid dynamics (CFD) technique and obtained temperature profiles
within the kiln using the three crucibles. Ultimately, we carried out standard mechanical tests on
the resulting metal parts and evaluated the thermal debinding procedure under various conditions. The approach we employed, combining experiments and numerical simulations, demonstrated significant promise for enhancing the quality of metal parts in the thermal debinding sintering process.”
Paper published to Heliyon on 2 April 2024 https://www.cell.com/heliyon/pdf/S2405-8440(24)04930-2.pdf