Experimental study on high viscosity fluid micro-droplet jetting system

Fluid dispensing is a method by which fluid materials (such as epoxy, adhesive, and encapsulant) are delivered in a controlled manner in electronics packaging. Fluid jetting, derived from inkjet technology, is a noncontact, data-driven fluid dispensing technology. But ideal fluid materials for packaging are usually high viscous, which is difficult to realize by traditional inkjet technology. In this paper, a mechanical micro-droplet jetting system for high viscosity fluid was proposed. It consists of dispensing valve, motion stage, temperature control subsystem, pneumatic subsystem, driving circuit for solenoid valve, and system control software. Performance of this system under various circumstances was studied by changing several parameters, including working temperature, stroke length, back pressure and drive pulse width. Tiny droplets of 0.35 mm in diameter were produced by stainless steel nozzle of 0.2 mm in diameter in the experimental study.