Modeling fluid–structure interaction in a direct write manufacturing process

This paper investigates the fluid–structure interaction (FSI) within a direct write manufacturing process. The interaction of three fields namely: electrostatic, structural, and fluidic in a continuous inkjet (CIJ) print head used for direct write manufacturing is captured with a multiphysics model. A FSI algorithm was used to capture the interaction of the piezoelectric (PZT) disc with different fluid media. The effects of input parameters such as fluid pressure, frequency, and voltage on the PZT disc displacement were studied. Further, their effects on the transient pattern of the PZT displacement are explained with respect to fluid type. The multiphysics model developed was validated by an ultra-high speed photography experimental setup. The outcome of this research concludes that fluids with higher viscosities display increased PZT disc displacements. Substantial rise in PZT disc displacements were observed with a proportional increase in the frequency of excitation. An increase in the density of the fluid resulted in higher PZT disc displacements. Thus, fluid density and rheology play an important role in the dampening behavior of the PZT disc as captured by the multiphysics model. For a particular fluid type, a minimal level of PZT displacement threshold is required for drop breakup from the fluid stream. Based on the findings of this research the input process parameters can be controlled to optimize microdrop formations that are critical toward direct write manufacturing.