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FLEXO Magazine : April 2010
30 FLEXO april 2010 www.flexography.org Figure 7: Today, it is possible to measure a sleeve before engraving to make sure the Tir is at an acceptable level. Figure 6: Significant improvements in direct engraving materials, combined with the improved laser technology, allow for direct en- graving plates up to 200lpi and higher. Figure 4: The basics of DlE. Figure 5: a fixed-position laser with a consistent focus that en- graves material on a moving bed offers the best quality. on one plate. How many times have you placed too much pressure for greater coverage of a solid and your type be- comes distorted or fills in? The solution in the past was to split printing decks. Now you can leave the solid at one level and the type below, allowing for heavy pressure on the solid and lighter pressure on the type. The same principle holds true for dots. Create highlight dots at one level and shadow dots higher than the highlight and mid-tone dots. How is it Done? CTP technology uses 1-bit tiffs. DLE can use 1-bit tiffs, but for the best performance, an 8-bit tiff or PDF is preferred. The tiff goes through another process where we assign the below-sur- face image, shoulder angle and relief depth. This is done using different gray values as seen in the center image of Figure 4. These gray values control the final image that we see in the right-hand image of Figure 4. This shows the basics of DLE. wHat’s so special? As technology improves, so does laser performance. One improvement in DLE is laser beam consistency. Lasers require consistent power for image cutting in order to achieve the level of quality required by flexo. Today ’s lasers offer this consistency. The introduction of stationary or static lasers has also improved performance. Better quality is realized with a fixed-position laser having a consistent focus that engraves material on a moving bed (Figure 5). There have also been significant improvements in direct engraving materials that improve quality and reduce process- ing time, in addition to advancements in post-process plate cleaning. These material improvements, combined with the improved laser technology, allow for direct engraving plates up to 200lpi and higher (Figure 6). Laser-engraved plates support the industry ’s movement to sleeves and/or in-the-round (ITR) technologies. Direct engrav- ing an elastomer on a sleeve is a great way to perfect regis- tration. With current software, creating an endless design is as simple as dragging an image into a template. Today, it is possible to measure a sleeve before engraving to make sure the TIR (total indicated runout) is at an acceptable level. This ensures that every sleeve is acceptable before engraving for the accuracy required when on press (Figure 7). Direct engraving has come a long way from its infancy and can now deliver the finest plate quality imaginable. Direct engraving is a flexographer’s dream. n ABOUT THE AUTHOR: Paul Zeinert has worked for Anderson & Vreeland for the past 26 years and is responsible for direct engraving, which includes equipment (Stork Prints) and materials (AVCE direct engraving material) sold by Anderson & Vreeland. He has 28 years of flexographic experience and has been actively involved with the FTA as a speaker and has served on the FTA Awards Committee for the past 10 years. Thinking Thermal? You Have Choices. MacDermid Printing Solutions is a leading supplier of thermal plates and processing tecnology. Our digital photopolymer sheet plates are unique in that they can be dual processed either in traditional solvents or using MacDermid’s LAVA thermal processing equipment, you choose. MacDermid also offers the only digital capped plate in the world, which can be dual processed. So before you take the next step in your plate processing work flow, take a look at what MacDermid has to offer. When you’re looking for the most flexible range of options in taking your operation thermal, count on the company that says “Yes We Can” . MacDermid. NotSoFastNotSoFast Think You Only Have ONE Choice? Photopolymer Plates Equipment 5210 Phillip Lee Drive, Atlanta, GA 30336, USA Telephone: +1 800.348.7201 www.macdermid.com/printing © 2010 MacDermid, Inc. All rights reserved TEchnologiES & TEchniquES FLXApril10_mech.indd 30 4/10/10 1:22 AM
Sustainable Winter 2010