Dymotek uses a two-shot process, eliminating operations and tooling to create a two-part, low-dose pump for a coffee-dispensing machine developed by Vitality Foodservice. After PEI resin is injected into a 4+4-cavity mold, it is exposed to ultraviolet light to enhance adhesion of overmolded liquid silicone. Because the PEI resin is processed at a temperature of 180C, the silicone cures rapidly when injected over the pump body. This approach cuts the cycle time for the part to less than 1 min - a savings of more than 2 min over an alternative concept using polycarbonate.
"Although polycarbonate is less expensive than Ultem (PEI) resin, we were able to come out ahead in terms of total cost with the SABIC Innovative Plastics material because its higher processing temperature speeds up silicone curing in the mold," says Victor Morando, vice president of engineering services, Dymotek, Ellington, CT.
Functional elements consolidated in the pump body include a flexible pumping chamber and inlet pinch valve, a cone-sealing element for the outlet valve, a seal for the nozzle insert, a seal for the fitment into the bag connector and a translucent window for the LED product sold-out indicator.
In the new Vitality pump, called the Bump Pump, a component moves downward into a variable rate pump with the pouch held above in a support structure, delivering a dose of concentrate that is combined with water for a finished drink. Click here for more information on Dymotek.