New retraction valve bridges the gap between high-end and entry-level direct dispensing

DELO Industrial Adhesives has released a new retraction valve to its lineup of adhesive dispensing systems. DELO-DOT RE fills a vacant space in its equipment portfolio, delivering much of the repeatability and control of higher-end systems like jetting or volumetric needle dispensing in tandem with the ease of direct dispensing from cartridges.

Enabled by compressed air, the pneumatic retraction valve offers many properties which promote a high level of repeatability and help provide 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 and stopping dripping.

The valve can dispense adhesive droplets as small as 0.09 µl. This is far lower than other retraction valves available or adhesives that are applied directly from cartridges. Also, 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 33mm x 25mm x 112mm, it can be readily integrated into almost any production line, needing only an additional 18mm to accommodate for its width. The same goes for its weight, which, at less than 100g, helps make minimal impact on existing systems.

Its actuators are hermetically separated from the dispenser's fluid system, which delivers simple, tool-free assembly and disassembly. Tool-free cartridge replacement is also achievable via spring-loaded reinforcement clips located on the actuator component. Unlike volumetric valves, any part of the valve that comes in contact with fluid at any point is completely 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, therefore increasing yields. Semicon lid attach is often performed via direct dispensing as well. Here, the valve's retraction mechanism delivers the control necessary for bondline thickness continuity.