If you make rigid boxes, chances are you have dealt with turn-ins that have popped open. Annoying. We know!
There are several reasons that you may be experiencing pop-opens, but one that we have seen more and more recently is pop-opens as a result of compression issues.
Put your hand up if you have made a box where 2 or 3 turn-ins adhere properly, and the others pop-open? Go ahead, I'll wait.
We've all been there.
The good news is, this is not a glue formula issue (whew!). If some of your box wrap turn-ins are popping open and others are not, this is typically the result of a compression issue.
When it comes down to it, glue is not “smart” enough to work properly on some turn-ins and not others. The only way this would be a glue issue is if the substrates on some turn-ins are different than the others.
You’ll want to make sure that the proper compression is used on the box line.
For example, on an Emmeci box making machine you'll need to check that the compression at the "plunger" and "form" is set to the proper and recommended settings. If you are unable to adjust the compression in-house, it is best practice to reach out to your equipment manufacturer directly for assistance.
If you notice that the turn-ins are still not adhering properly, make sure that your glue is not running too cold. If it is too cold, by the time the trailing edge is compressed, the glue may have already set and will not bond properly.
You can find the recommended application temperatures of your glues Technical Data Sheet.