German adhesives and equipment manufacturer DELO Industrial Adhesives has added a new retraction valve to its lineup of adhesive dispensing systems.
DELO-DOT RE offers the repeatability and control of higher-end systems like jetting or volumetric needle dispensing and the simplicity of direct dispensing from cartridges. Enabled by compressed air, the pneumatic retraction valve features properties that support a high level of repeatability and help ensure a quality bond, according to the company. Its retraction mechanism enables heightened precision and control. Following dispensing, rather than simply ceasing air compression, the needle pulls back slightly to reverse the flow of adhesive. This creates a vacuum effect to curtail adhesive flow and prevent dripping.
DELO-DOT RE can dispense adhesive droplets as small as 0.09 µl, which is smaller than applying adhesive directly from cartridges. It dispenses with a standard deviation of less than 3%, much lower than direct dispensing via cartridge and in line with many higher-end jet valves.
At 33 x 25 x 112 mm, the valve can be integrated into most production lines, requiring only an additional 18 mm to accommodate its width. A weight of less than 100 grams has minimal impact on existing systems.
The 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 into 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,” the company said. “Semiconductor lid attachment is often performed via direct dispensing as well. Here, the valve’s retraction mechanism provides the control necessary for bondline thickness continuity.”
Source: DELO
