Jetting: A New Fluid Dispensing Technology

A fluid dispenser includes a dispense mechanism that provides for increased mechanical advantage. The dispense mechanism includes a lever member and an actuator. The lever member includes a first lever section that receives application of an input force and a second lever section that applies an output force to the actuator which leads to the dispense valve. The lever member and/or the actuator are configured to provide at least two contact points between the actuator and the second lever section during the course of a dispensing stroke such that the mechanical advantage provided at a first one of the at least two contact points is greater than the mechanical advantage provided at a second one of the at least two contact points.

There is a new way to dispense fluid which is better and more efficient, it is called jetting technology. In jetting, fluid is rapidly ejected through a nozzle in discrete droplets. Jetting is a preferred method for dispensing fluids for a number of reasons. This includes productivity increase through the reduction of up and down vertical height movement, improved resolution for dispensed fluid weight and volume, and high, controlled fluid flow rates. Jetting has evolved to become a standard production process equipment in many industries, and now accommodates a wide variety of fluids and applications. Everything from more intricate, emerging technologies — which include stacked die, fuel cells, LEDs, flat panel displays, and lab-on-chip — to MEMS packaging and more traditional packaging turn to an array of jet valves and complete dispensing systems with closed-loop process controls for mass production. This new jetting technology is also made by large pressure tank manufacturers all around the globe.

Automated jetting for fluid dispensing in electronics assembly and precision manufacturing was pioneered in 1994 by ASYMTEK as a replacement to traditional needle dispensing. Improvements to production consistency, accuracy, repeatability, reliability, and speed have been driving jetting technology developments for years. Advances in jetting processes have made it the default fluid dispensing method for advanced package designs that require placing very small dots of fluid into tight spaces. The high cost of these packages demands an extraordinary degree of dispense-volume accuracy to ensure high production yield. With so many jet valve and jetting system options available today, the question turns from whether or not to use a jet, to one of which jetting system is best for a particular project, or which system is most versatile and addresses the widest variety of possible applications.

Jetting is faster than traditional, contact-needle dispensing because Z- axis motion is not required for the dispensing and fluid break-off from the nozzle. The jet “flies” over the substrate and shoots precise, controlled volumes of material to form pre-programmed dots and line patterns.

Additionally, because jetting enables larger dispense gaps between the nozzle orifice and the substrate and the fluid breaks off from the nozzle in a thin stream, dispensed fluid can be targeted closer to a component, or the edge of a die, and into tight places. This enables smaller keep-out zones around mounted board components, especially useful for under filling flip-chip, package-on-package (PoP) or stacked-die applications. To create different dot sizes, the jet hovers over one location, depositing additional dots. Actuation frequencies of most of today’s jet valves typically vary between 200 and 1000 dots per second, which enables quick multi-dot dispense patterns.