Additive manufacturing of complex-shaped copper parts via binder jetting (BJT) may be transformative for industry applications such as thermal management and electrical systems. In order to produce these complex structures with intricate features in BJT, process parameters must be tailored such that components have suitable strength to be de-powdered without excessive binder bleeding. Excessive bleeding can result in distortion or obstruction of features. Binder saturation, defined as the volumetric ratio of binder deposited to voids within the powder bed, is one such process parameter which affects both the strength of the green (after printing, before densification) parts as well as the achievable resolution of fine features. This work, done in collaboration with Kymera International, proposes to examine the effect of varying binder saturation on the dimensional fidelity of fine features in both the green and sintered states. Mechanical strength of green parts will be tested using the three point bending test (ASTM B312). Dimensional fidelity will be evaluated using image analysis techniques to compare achievable feature size to that of the CAD model. Optical dilatometry will be implemented to observe the shrinkage and distortion of fine features in real time during the sintering process. Additional furnace sintering results will be presented to showcase final part density and thermal/electrical outcomes.
Learning Objectives:
Express the effects that binder saturation will have on the resolution of fine or intricate features in both the green and sintered state of binder-jetted parts.
Describe the trade-off between the mechanical strength of green parts, feature resolution, and sintering outcomes as a result of varying binder saturation.
Understand the benefits of compensation factors in binder jetting to reliably produce dimensionally accurate features at a lab scale and beyond.
