Enabled by compressed air, the pneumatic retraction valve features many properties which promote a high level of repeatability and help ensure a quality bond. Heightened precision and control come from its retraction mechanism. Following dispensing, rather than simply ceasing air compression, the needle “retracts,” pulling back slightly to reverse the flow of adhesive. This, in turn, creates a vacuum effect, curtailing adhesive flow without delay, preventing dripping.

DELO-DOT RE can dispense adhesive droplets as small as 0.09 µl. This is much lower than other retraction valves on the market or applying adhesive directly from cartridges. In addition, it dispenses with a standard deviation of less than 3%. This is much lower than direct dispensing via cartridge and is in line with many higher-end jet valves.

At only 33 x 25 x 112 mm, it can be easily integrated into almost any production line, requiring only an additional 18 mm to accommodate for its width. The same goes for its weight, which, at less than 100 grams, helps make minimal impact on existing systems.

Its actuators are hermetically separated from the dispenser’s fluid system, which results in simple, tool-free assembly and disassembly. Tool-free cartridge replacement is also possible via spring-loaded reinforcement clips located on the actuator component. Unlike volumetric valves, any part of the valve which at any point comes in contact with fluid is entirely encapsulated and can be easily replaced.

All these properties culminate in many possible application fields. In semiconductor potting, as well as active alignment processes for cameras, dispensing directly from the cartridge is often preferred. However, unlike in direct dispensing, the retraction valve does so without dripping or bubbling, thus increasing yields. Semicon lid attach is often performed via direct dispensing as well. Here, the valve’s retraction mechanism provides the control necessary for bondline thickness continuity.