September '21

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Y ou have this awesome UV printer and want to print on anything and everything, right? Or maybe you have a new product for your UV equipment that can boost profits? Either way, you'll need a print that sticks well to the product and more than likely, one that stands up to some wear and tear. It's true that UV printing offers a range of products and materials that set it apart from other decoration methods. However, you must keep in mind that the material you print to may require different process- ing steps or print settings to achieve a long-lasting print. WHY CAN ADHESION BE A CHALLENGE? I was at a trade show many years ago and overheard this during a networking event: "We can definitely print on that product. That's easy. It is the adhesion I'd be worried about." As I listened to that, I shook my head in disbelief. While the statement is factually correct, the UV print veteran in me says that the statement is false. A high-quality print with proper ad- hesion is what it really means to "print on that product." So why can it be a challenge? I don't want the readers of this article to think every product is a challenge. It is actually the op- posite. There are many products and mate- rials that are simply load and go: You load the printer, set your art file with standard settings, hit print, and you are left with a beautiful and long-lasting print. Then there are the other materials or coatings that can be a challenge for printers in general. Common tough-to-print materials include glass, stainless steel, brass, and polypropylene. Remember, UV prints don't penetrate the surface of the material like a solvent ink does as it sits on the surface. The aforementioned materials (among others) could have surfaces that don't have what some refer to as a lot of "tooth or bite," or they could have special coatings and release agents on them for the purpose of not having things stick to them. It isn't rocket science to overcome these challenges by dialing in the printing steps. There are simple, manual solutions to try for low volumes, and then there are treatment systems that can help you consistently maximize production. I want to keep this piece fun, light, and informative; however, I must put on my lab coat and include this highly educational statement: Many of the options discussed going forward change the surface tension or dyne level of the treated product. That change is what produces a better surface for UV ink to adhere to. It's all about surface prep and it can be simple to achieve. But enough of the scientific terms. I want you to get back to printing, so let's look at some solutions to your challenges. 3 4 D I R E C T - T O - S U B S T R A T E R E P O R T 2 0 2 1 G R A P H I C S - P R O. C O M DIRECT-TO-SUBSTRATE REPORT A PRINT THAT STICKS AVOIDING ADHESION CHALLENGES IN UV PRINTING B Y M I C H A E L P E R R E L L I Above: A view of the dual flame and Pyrosil treatment by the PYROBOND 4 GL System. Left: An example of an adhesion promoter that would be hand-applied prior to printing. (Images courtesy Michael Perrelli) way, you'll need a print that sticks well to the product and more than likely, one that stands up to some "We can definitely print on that steel, brass, and polypropylene.

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