Design and performance analysis of a piezoelectric jetting dispensing valve

Abstract

In order to meet the requirements of high frequency, high precision, and micro-scale dispensing in the field of microelectronics packaging, a piezoelectric jetting dispensing valve based on two-stage displacement amplifying mechanism was proposed. First, the overall structure and working principle of the proposed piezoelectric jetting valve were described. The displacement amplifying mechanism was designed, and the mathematical relationship between the output displacement and the structural parameters was established. In addition, the performance and the structural size of the displacement amplifying mechanism were analyzed and optimized by using the finite element analysis software. The influences of driving pressure, glue viscosity, needle displacement, and other parameters on droplet diameter and jetting velocity in the process of dispensing were simulated and analyzed. In order to obtain the optimal nozzle structure, the changing curves of glue flowing velocity with different nozzle seal forms, nozzle cone angles, and outlet inner diameters were compared and analyzed. Finally, the prototype of the piezoelectric jetting dispensing valve was machined, and experimental study was performed. The influence laws of driving pressure, glue viscosity, driving voltage, and other parameters on the diameter of droplet were explored. The performance of the prototype was evaluated from three aspects of dispensing frequency, consistency, and minimum dispensing droplet diameter. Results show that the highest dispensing frequency is 230 Hz, the deviation of dispensing consistency is ±8.77%, and the minimum dispensing droplet diameter is 0.54 mm. The experimental results verify the high frequency, consistency, and micro-scale dispensing performance of the piezoelectric jetting dispensing valve based on the displacement amplifying mechanism, which provides a reference for the research of piezoelectric high-frequency jetting dispensing.