Do Extended Glue Tabs Help Skew
By Ralph Young
November 9, 2023
Bryan asks:
We have several items that we are producing with an extended glue tab.
The extended glue tabs are added on most of these items, as the items have a small body (under 5 inches).
The extended glue tabs are added on some of these items as a corrective action for an old machine that we had that produced a lot of skew. Not sure that this theory even truly works, but someone before me thought that it did.
I am reaching out to you to ask, are extended glue tabs necessary for small body boxes? Do they actually do anything for the integrity of the box or is this something box makers have made up in their heads?
Well Bryan, I must admit the way you asked your questions did make me grin. There’s not a one-size-fits-all answer for these questions. Let’s look at the skew questions first. I don’t believe there are any engineering specs or TAPPI standards that offers this as an option for resolving skew. However, depending on the machine design, especially your counter ejector, it’s possible this may help with skew. Skew occurs when one or more panel scores are torqued, twisted, or pushed out of square. Then when the tab is glued to the panel they aren’t square to one another and you have skew. Often a crew will try to fix this in the counter-ejector by spanking the boxes a little harder. This can work quite well… If…the skew is not excessive, the glue has not set before it enters the counter-ejector, and the glue firmly sets before the boxes are ejected from the counter-ejector hopper. So… an extended glue joint would provide more surface area for gluing, even if the glue has not fully set you would still have more area that hard cured than you would with a standard tab. If you get the joint square at some point, the extended tab could help you minimize or eliminate skew. So, it is possible it helps on your machine. The only way to know if it is really necessary is to try running without it. Questions #2. The easy answer is no. Extended glue tabs are not required for small body boxes. While that’s the easy answer, it’s not a one-size-fits-all answer. The extended tab does help with the integrity of the box, but the question is if you really need it. It comes down to the purpose of the box. Will it contain something that is heavy? Will it be subject to a lot of crush pressure? Is the customer requiring it for some reason? What’s the overall area of the box? Hope this helps. And as usual, if any of our readers would like to contribute their knowledge and experience, we’d be happy to share it! — Ralph
Technical questions?
