July 12, 2012
It is necessary to treat any material when you want to improve the adhesion of inks, coatings or adhesives. Most commonly plastic films are treated but it is also necessary to treat foils, paper and synthetic materials. Treating generally works best for films when they are being extruded or in-line just prior to printing. Treating basically increases the surface energy of a material and in so doing improves its wettability, which is what helps the adhesion of your inks and coatings to it. It is worth noting that all treatments diminish over time so you should run as soon as a material has been treated or at least be able to retreat it in line just prior to printing.
July 2, 2012
With new press designs, higher press speeds are indeed setting a new challenge for printers and mounting tape manufacturers alike. Conventional hard vinyl cheaper tapes may have been suitable for some at lower speeds but higher press speeds present a new set of dynamic issues that demand consistent compression and rebound capability of the tape to last through the entire run.
Foam sticky back materials seem to struggle at higher speeds and new elastomer cushion and higher temp resistant adhesives appear to be able to cope better. There are obviously a wide variety of tapes each with their own features and with the many other variables on press it really means some due diligence on you and your supplier’s part to try out a variety of tapes to help determine what works best for you with each plate material that you may be using.
Inks, substrates, even plate cylinders all have a profound impact on the eventual dot gain you will see, not forgetting the operators skill at setting the optimum pressure between the plate to substrate, anilox to plate, blade to anilox and even doctor roll to anilox. This evaluation all takes time, patience and perseverance as it is rare that you will be able to get the right combination from the outset. There is no doubt that the more experience your supplier has the better your chance of finding what will work best for you. Do bear in mind that your prepress can have a profound impact on also helping to minimize your doubt gain by making the necessary allowances at the file separation and screening stage, not forgetting your anilox and ink supplier, so you must involve all of your suppliers inside and out if you what to achieve the best result and help you decide what is right for you.