We often get questions from our customers about single-sided laminating and paper thickness. In this proTIP, we discuss some of the common issues and solutions that you can try.
First up, thin paper.
The most common issue we see here is wrinkling. You may be running 80lb stock for wraps for book covers, for example. But what happens is the pressure of the lamination roller is too much for the paper, and this causes a boat-wake wrinkle into the center of the sheet.
To correct this, we recommend running the paper grain perpendicular to the way that the sheet is traveling through the machine. This gives the paper more structure to resist the wrinkling that might typically happen.
The other thing you should try is reducing the pressure. You should be using the minimum amount of pressure possible while getting good adhesion results.
Thick paper poses an entirely different issue.
In this case, it's often a matter of what the machine can handle. We often see skidding, jamming or the sheet simply won't feed if it's too thick to get through the nip rollers. Other times, the rollers gap to allow the sheet through, and then bounce close, leaving a mark on the sheets. If you're commonly seeing any of these issues, you may want to consider upgrading your laminator to one that can handle thicker stocks.
For example, the Bagel Systems' Digifav successfully runs thick stock by allowing operators to adjust the feeder so that instead of overlapping the sheets, it butts them together as they go through. This means that the nip is no longer fluctuating and bouncing, giving us a much smoother process. And where a traditional flying knife would fail at separating the sheets at the output, the Digifav does this perfectly.
Another thing to consider when you're running thicker stock is that the pressure is already increased, simply because the stock is thicker. This commonly causes over-curling, and even with a traditional de-curling device, it's hard to flatten out. So, again, reduce the pressure to the point where it's as low as you can go while maintaining good adhesion results.
On our high-end laminators, you have the ability to mechanically limit the pressure of the nip rollers. This allows you to mechanically set the gap of those nip rollers to the point where it's still applying enough pressure, but it's not crushing the sheet.
Keep in mind, though that there are other factors that could affect your lamination results. E.g. humidity, temperature, how long the prints have rested before lamination, etc. But for each new job, it's always a good idea to run 5 or 10 sheets and make sure you've got the best adhesion and all your settings are where they should be.
If you have questions about a specific application, feel free to contact us at 1.888.820.9020.