The concentric squeeze-mode piezoelectric print-head (PPH) has been applied to the field of additive manufacturing, which requires a high deposition precision of droplets. To combine the self-sensing technique of a PPH, this paper presents a linear time-varying system equivalent circuit model based on radial displacement. This system is able to predict the flow state in the channel according to the variation of the pipe diameter. Compared with current models, this equivalent circuit model is more accurate in regard to energy attenuation. The equivalent thickness of the boundary layer is presented using a combination of boundary layer theory and oscillating plate flow to calculate the equivalent resistance of the viscous force. The experimental results show that the proposed method is more precise than the previous equivalent methods. To verify the model, a single trapezoidal pulse waveform and double trapezoidal pulse waveform were designed to realize the superposition of pressure and suppression of residual oscillation, respectively. The experimental results showed that the single trapezoidal pulse waveform based on the modelled pressure response was able to exactly realize the superposition of pressure and that the double trapezoidal pulse waveform based on the modelled pressure response was able to suppress the residual oscillation. The pressure and volume flow rate responses of the model are highly consistent with the experimental results in the time domain.
Wang J , Huang J , Peng J . Hydrodynamic response model of a piezoelectric inkjet print-head[J]. SENSORS AND ACTUATORS A, 2019.