Design and Experiment of a Jetting Dispenser Driven by Piezostack Actuator

To make up for the insufficiency and instability of contact dispensers that are used for fluid dispensing in microelectronic packaging, a noncontact jetting dispenser driven by a piezostack actuator is introduced in this paper. After describing the structural components and operating principle of the dispensing mechanism, a fluid model is presented to discuss the dynamic properties of the fluid and analyze the key parameters of the proposed dispenser. The ANSYS simulation software is used to design the displacement amplifier, which is an important component of the dispenser. The maximum displacement output of 323 μm is obtained by optimizing. Subsequently, the dynamic behavior of the displacement amplifier is measured by an optical displacement sensor. The displacement change with the driving voltage amplitude and frequency is also investigated; the maximum displacement is 320 μm, and the error between the simulation and the measurement result is just 0.75%. In order to verify the practicality of dispenser, experiments are conducted to examine the effects of the driving voltage, backpressure, working temperature, and distance between the nozzle and the collector on the jetting performance and droplet diameter. The dispenser can dispense droplets uniformly and steadily. Its maximum jetting frequency is 65 Hz, and droplets of 1.07-mm diameter are produced by a stainless steel nozzle of 0.25-mm diameter in the experimental study, with the variation of the droplet diameter being within ±2%.