One of the most common issues that many packaging line operators experience with their adhesive melter is stringing. Stringing is when the adhesive is applied to the box, but before the flaps are closed on the cartoner, the glue starts to dry and string like cotton candy floating through the air.
There are a couple of fixes for this issue. Whether you are using a straight, right angle or swirl pattern nozzle, try moving the applicator gun closer to the box flap where you are applying the adhesive. The stringing could be caused because it is travelling too far of a distance from the applicator gun to the box. The shock from hitting the cooler factory air could be causing it to lose viscosity and start drying before it even hits the box. Not only will that cause stringing, that might also compromise the integrity of the glue hold on your product packaging.
Another cause of stringing glue could be temperature. Every adhesive is different and each one might require a different melt temperature. In order to keep the adhesive a consistent viscosity, make sure that the temperature on your glue tank and applicator guns are set correctly per the adhesive requirements. If the adhesive is too viscous then you might need to increase the tank temperature or change to an adhesive with a lower viscosity. If your tank temperature is correct, but your guns are not hot enough, then the glue could start to cool while travelling from the tank to the applicator gun. In this scenario, you would see that the thickness of the glue as it leaves the nozzle. Some line operators might try fixing the issue by putting a larger diameter nozzle on the module, which could be a temporary fix, but the real issue could be the temperature setting on the gun. Simply increase the gun temperature as needed to ensure a smooth, consistent adhesive flow.
There could also be an issue with the adhesive you are using on your packaging line. Like many products, if the adhesive is too old, has been sitting for too long, or has been heated and cooled too many times, this could cause stringing. We recommend that you drain all old adhesive from your tank, clean the tank with a cleaner such as Purge Plus™, and refill with fresh adhesive.
Universal Systems SE recommends trying to correct stringing if it is happening to your packaging line. Some line operators may think it is not that big of an issue, or they might blame the adhesive manufacturers, when in fact it could be a simple and important fix.
For more information or technical support to help you better understand how to fix your stringing glue, please call Universal Systems SE at (561) 272-5442 or email firstname.lastname@example.org.