Authors: C.-H. Wu, W.-S. Hwang
Affilation: National Cheng Kung University, Taiwan
Pages: 540 - 543
Keywords: monopolar waveform, fluid propagation, simulation
For inkjet printing, the fluid dynamics in a capillary tube caused by the movement of the piezoelectric material is essential due to the need to adjust the voltage pulse waveform, but it has seldom been observed and measured. Some studies have found pressure variation in the tube by measuring meniscus motion or using a laser Doppler vibrometer. However, the contribution of each voltage pulse is not clearly known. This study investigates the pressure wave propagation of molten solder induced by a voltage pulse using a numerical simulation method. Micro droplets of molten lead-free solder, Sn3.0Ag0.5Cu, were ejected at 230 °C using a squeeze-mode piezoelectric inkjet printing process. Simulation results, which are verified by experiment results, are used to examine the fluid dynamics in a capillary tube. The pressure wave propagation direction is determined and the effect of each voltage pulse is discussed. The results can be used to optimize parameters to obtain the desired droplet properties.