UV adhesive was applied by a well-known car component supplier onto operation of closing small housings, with 6 axis robot. The manufacturing line was built in Sweden, transferred to Poland, and dispensing was done based on on/off low pressure valves. However, dispensing was lousy due to two reasons:
* When pressure in pressure tank was higher than 1 bar, adhesive absorbed air, which created bubbles.
* To eliminate bubbles, dispensing was done extremely slowly, so production output was much too low, especially when material hoses from tank to valve were 2 meters long.
Additionally, repeatability was inconsistent, what was smaller issue, not important to customer.
In fact, the main reason for preeflow® presentation was request to dispense grease on micro coils, where shots of two sizes: 0.02 and 0.03 grams were demanded by OEM, and this parameter was unreachable for normal dispenser. Glue line was located 3 meters from greasing station, and adhesive bonding was discussed as additional issue.
When preeflow® pumps were used, supply method was good enough: UV glue is delivered by small pressure ca. 1.0 bar only, which does not harm adhesive with bubbles. Meanwhile eco-PEN 450 allows 3x flow increase giving much bigger line output. Bubble-free dispensing, of course!