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FLEXO Magazine : March 2010
www.flexography.org MARCH 2010 FLEXO 27 quickly. The good news is that most small chips, and sometimes bigger chips, can be repaired without having to have the roller recovered. Your doctor blade company and some anilox roller suppliers should have an epoxy repair kit made for ceramic available to help you with this. There is an art to using the epoxy and certain materials are needed when smoothing it down to make sure you end up with a perfect radius. Again, check with your supplier. He or she can be a valuable resource. MATERIAL WORLD Now let's touch on the different mate- rials used for end seals. The proper ma- terial for the specific type of inks used is a good start. Most end seal material will work enough to get by for just about all different types of inks, but getting by is not what we are looking for. Foams generally are the cheapest material and for some printers they can be a good fit. Long runs, higher press speeds and solvent inks can be better suited for felt, neoprene or rubber seals. This is an area where you need to work with your supplier. I have observed an end seal fail using one type of ink where another company will have the exact same press and similar inks and the same seal works great. Another important thing to note is that different densities of the same material are often available to you. Sometimes a super- firm seal does a great job. Sometimes a seal that is more collapsible and con- forms to the chamber is more suitable. Once again, work with that valuable resource: your supplier. Lubrication is a key area that many printers don't pay enough attention to. The proper type and amount of a lubri- cating agent can extend the life of the seal by obviously reducing the friction between the roller and seal but also by helping to repel the ink so that harmful build-ups don't occur. Most felt seals will come pre-soaked with petroleum jelly. It is still a good idea to keep some jars of this available in case more lubricant is needed. I have seen a food-grade lubricant used with solvent inks with good success. Since they can be water- based, the solvent does not break them down as quickly. In most cases, all seals should have a lubricant applied to them before use. Let's say you do have issues with end seals leaking what's your incentive to do something about them? Is an item costing $3.00 or less really worth the effort? In order to justify spending your all ready hard to come by time on a project, you need to have a return on your investment to look forward to. Well, first of all, a clean press runs better. A clean press makereadies better. Opera- tors take more pride in their jobs on a clean press. Secondly, as I mentioned, adding extra pressure to a chamber is often the first thing any operator will do to stop an end seal leak. The extra doc- tor blade wear is costly, but how about the wear on the anilox roller? Consider the quality issues that can happen when overloading a chamber. TRY, TRY AGAIN It may take several attempts for you and your supplier to find the proper end seal for your application. It will take follow up and good communica- tion and some patience and diligence on your part. There is a lot that goes on behind the scenes to modifying an end TECHNOLOGIES & TECHNIQUES 800.346.8570 www.colorresolutions.com brand identity. Custom for mulated flexographic inks and coatings fr om CRI pr ovide brilliant high-gloss colors and a durable scratch and rub-r esistant finish. Combined with CRI's unique TrueColorBalanceTM color management system for superior process contr ol, your printed labels will become an integral part of your customer's brand pr omise. And, you'll get the benefits of water-based inks that are among the most earth-friendly, with extr emely low VOC's and minimal envir onmental impact. Contact a CRI technical specialist for fast response to your ink and color application questions. Give your labels a new twist.
Sustainable Winter 2010