by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
FLEXO Magazine : July 2014
Below Surface Engraving Below surface engraving gives the ability to three dimensionally control the dot height, shape, surface size, shoulder width and angle, and relief depth of both halftones and text. Below surface engraving reduces the risks of printing shoulders and inconsistent dot gains. Control of the shoulders allows for razor sharp text even at one and two point, and the ability to print smaller reverse text without “filling in.” Imaging with a direct laser can create stronger dots than that of the laser ablated mask system used in polymer plates and sleeves. The First Kiss We’ve developed a set of best practices for establishing kiss impres- sion when running fingerprints. We start the fingerprint process by familiarizing ourselves with the press operators. Some may have never run sleeves before and we may need to provide specific training for mounting those sleeves. When mounting, some left to right jog is OK, to mount the sleeve on the air mandrel — but the tendency is to “over waddle” the sleeve, which can cause significant damage to its ends. This is true for printing sleeves, bridge mandrels and bridged anilox sleeves. It’s important to maintain the integ- rity of the ends of these compo- nents by not damaging them when they are mounted to and removed from the press. Damaging ends can cause TIR issues in the future and sleeve edges that are slightly higher than the middle. For production runs, damaged ends will require over impression to get everything to transfer across the web. We then remove all pressure from the CI roller to the elastomer sleeve and from the anilox to the elasto- mer sleeve. With ink flowing, we bring the anilox to the sleeve, then slowly kiss the impression to the substrate. We make a note of how evenly the print transfers across the web. As this is done, some ques- tions we consider are: • Does it crown? • Is it lighter on one side versus the other? • Does it require additional impression to achieve 1 percent to 2 percent dots? If I’m satisfied with the results, then we’ll speed up the press to bring it into production spec and pull sheets to evaluate. At this time, we look at the Carey Impression Targets on both sides of the web, in the trim. These circles are made up of various percent dots in circles: • 100 percent • 5 percent • 4 percent • 3 percent • 2 percent • 1 percent The dots in those circles are designed to progress gradually from below surface at 1 percent, then higher at 5 percent, and then to surface level at 100 percent. We work with the press operator to quickly evaluate the impression from the left to right at any point in the run and build or evaluate the curves based on real data on impression. In Example 1, the dots on the left side of the sleeve are slightly over impressed, while the dots on the right side are slightly under impressed. An experienced pressman would be able to make the necessary adjustments quickly. It is our goal to implement this type of impression calibration on all jobs and we encourage our customers to use our Carey Dots in the trim, to measure impression. The dots are a useful tool that give an operator immediate data on the current impression level. This way, a pressman can know whether he needs to increase pressure or back off. And they have a tool for calibrating the pressure on both sides of the web. — Adam Smrdel, director of flexography, Carey Color Inc. Example 1 26 FLEXO | JULY 2014