Droplet Dynamics Evolution and Precision Control of Non-Newtonian Fluids in Inkjet Printing for Multilayer Ceramic Packaging Substrates

Satellite droplets and macroscopic distortions, induced by the non-Newtonian rheological behavior of ceramic inks, severely compromise the 3D inkjet printing of multilayer ceramics. To address these issues, we establish a two-phase fluid dynamics model coupling the Level Set method with the Carreau fluid model. The synergistic regulation mechanisms of the piezoelectric driving waveform, initial jet velocity, and pulse width under a high-shear field are elucidated. The results demonstrate that under the excitation of a rectangular pulse with an initial jet velocity of 6 m/s and a pulse width of 10–30 µs, the inertial force, surface tension, and internal non-Newtonian viscous dissipation of the fluid reach an optimal dynamic balance. This facilitates the on-demand ejection of spherical droplets while mitigating the formation of satellite droplets. Based on this, a 10 mm × 10 mm × 2 mm multilayer alumina ceramic packaging substrate was successfully fabricated, with the maximum relative dimensional error reduced from 2.6% to 1.4%. This study provides new insights into improving the 3D inkjet printing accuracy of ceramic devices.