Development of a Piezo-Driven Liquid Jet Dispenser with Hinge-Lever Amplification Mechanism.

Owing to the quick response, compact structure, high precision, huge blocking force generation, and ease of operation, piezoelectric actuators are urgently being adopted in the field of advanced dispensing for jetting performance improvement and fulfillment of precision requirements in microelectronics packaging, adhesive bonding, and miniaturization industry. This research focuses on the fundamental design and development of a piezo-electrically driven compact fluid dispenser using the principle of a class-one lever for amplification of needle displacement, and enhancement of application areas of the developed jet dispenser. Using fundamental lever principle, geometry-based modelling is carried out to fabricate a working prototype of a normally closed hinge-lever type dispenser. Preliminary experiments are carried out to witness the workability of the fabricated dispenser to deliver 100 dots of working fluid per second that will provide a novel device for dispensing of various fluids, and the proposed amplification mechanism suits various other piezoelectric applications as well.

Numerical Analysis on Piezoelectrically Driven Jet Dispensing Mechanism for Nanoliter Droplet of High Viscosity Liquid.

Various research on a dispenser head applied with the technology of piezoelectric ceramics which has high response, force generation and resolution have been actively conducted. A piezoelectric dispenser head for functional high viscous liquid generates micro droplets utilizing a different mechanism with conventional valves. This mechanism makes it difficult to calculate the pressure build-up and flow quantity. Because of this difficulty, proper displacement of a tappet cannot be selected and the displacement of the piezoelectric ceramic is being used with excessive amplification. To address these issues, a piezo dispenser head has been modeled to numerically analyze this mechanism. The mechanism has been simulated to calculate the pressure build-up and flow quantity. In addition, the load on the tappet was calculated, and the appropriate displacement of the tappet was confirmed. In this study, we have succeeded in numerically analyzing the mechanism of the piezoelectric dispenser head and we confirmed that the displacement of the appropriate tappet is about 200 µm; at this time the load on the tappet is about 3.7 N and the droplet volume is about 19.89 nL.