Occasionally we hear from a customer experiencing a problem with edges lifting on full bleed contour-cut decals. The most recent call concerned some decals printed on ORAJET 3651 vinyl and applied to a substrate. Edge curl on full bleed decals is most commonly seen in “Fatheads” style wall graphics, which rely on lower tack adhesives to enable the end user to reposition the decal at will. But edge curl can also occur on standard decals using permanent adhesives. What causes this and how can it be avoided?
Improper out-gassing can cause edge curl
The root cause of the problem is out-gassing; or rather the lack thereof. The solvents used to penetrate the vinyl and deposit the ink require about 24 hours to evaporate out of the media. According to Dean Strohmenger of ORACAL Tech support, this most often occurs when an image is printed, contour-cut, and then laminated. If you laminate a contour-cut decal without allowing proper time for out-gassing, the solvents become trapped under the overlaminate film, where they may begin to interact with the adhesive. Since the adhesive is also solvent based, this interaction can dilute the adhesive. Strohmenger likens it to adding water to a freshly finished watercolor painting. The area where that interaction is most likely to begin is along the exposed edges of the vinyl. The result is edge curl. That’s the bad news. The good news is there are several ways to tackle this problem: out-gassing, profiling, and laminating.Three solutions to prevent or minimize edge lifting or curling on full bleed contour cut decals
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Out-gassing: The simple solution is to wait for the print to outgas before performing the contour cut. Most experienced print service providers are familiar with the industry standard wait time of 24 hours before laminating. ORACAL’s recommendation is that all solvent or eco-solvent prints should be allowed to outgas for 24 hours before cutting OR laminating. If you contour cut the graphics right after printing, some edge curl is common. Waiting a day to perform the contour cut produces edges that lay flat and stay flat.
- Print the images, set them aside on a table where they can breathe for a day, then load them into cutter and finish the job. If you’re using a two machine system like most of our customers, this isn’t difficult because you’re moving the vinyl from the printer to the cutter anyway. Whether you’re using a PrismJET VJ48 and FlexiSign Pro or a PrismJET DT and JetCUT, the software facilitates this process because the RIP software holds the cut job in a queue until the media is loaded and the cutter is ready. Normally, this is only a couple of minutes, but if it’s a day later, the job is still there. So instead of print and cut, the preferred method is print, wait, then cut. Then mount and finish your decals.
- Profiling: Although uninstalled decals printed and cut immediately will begin to curl after a few hours, decals that have been printed, cut, and mounted to an industry standard substrate shouldn’t do that. If they do, you’re probably using too much ink which is usually caused by printing with the wrong ICC Profile (see our recent blog article for more information about correct profiling). Use of incorrect profiles can cause oversaturation. The excessive ink overloads the face film resulting in too heavy a concentration of solvents. As noted above, this weakens the solvent adhesive bond resulting in edge curl or eventual adhesive failure. Dean says that when he received a complaint about lifting edges, his first response is to verify that the right profile is being used. This will reduce the ink levels to their optimum range and enhance adhesion.
- Laminating: If you really want to make sure the edges stay flat, you can apply a layer of overlaminate film. Cut the overlaminate a little larger than the print so that the film extends beyond the edge of the decal and seals it. For prints on flat surfaces and simple curves, try our new PrismJET 100 Series calendared overlaminate film. It’s available in gloss, luster, and matte finishes. In addition to preventing edge lifting, it protects your prints from abrasion, detergents, and greasy fingerprints. Remember to wait 24 hours for the prints to outgas before laminating, or you’ll be trading one problem for another. You’ll find more tips about proper finishing of digital prints here.
By the way, one might think that an edge sealing pen would be a good idea. Not so. Strohmenger says using a seal-it pen to prevent edge curling instead of proper out-gassing would be like “putting a band-aid on a broken leg”. If it held the edge down, it would simply trap the solvents elsewhere in the print leading to more serious adhesive failure later. Of course, an edge sealing pen might be entirely appropriate AFTER you allow the proper time to pass so that our gassing could occur. Every digital graphic technology has its tradeoffs. Eco-solvent printing offers excellent outdoor durability, economy, and versatility. To fully enjoy those benefits, you must understand the processes involved and manage your workflow accordingly. Allowing solvent or eco-solvent prints to fully cure before cutting or laminating is a best practice that will enhance your decal's quality. This will increase customer satisfaction and ensure repeat business.
