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FLEXO Magazine : April 2010
28 FLEXO april 2010 www.flexography.org Technological advancements affecting flexo have dra- matically improved print quality over the years, and with the recent introduction of direct laser engraving, quality has now improved by a quantum leap. The role of the flexo plate is pretty simple; to carry or transfer ink from the anilox roll to the substrate. So simple, yet so complicated. The problem is gain that results from applying pressure to transfer ink from the plate to the substrate. The more pressure that is placed on the substrate the more ink lays down result- ing in spread. The solution is to place the smallest image possible on the plate and lay down less ink. CTP (computer-to-plate) technol- ogy achieves this with a laser and special plate with a black layer that creates a mask. While the benefits of CTP are impressive, the technology only allows for the manipulation of an image in two dimensions. What if we could control an im- age in three dimensions? What if we could control pressure? This would be a flexographer ’s dream! DLE (direct laser engraving) uses a precision laser to cre- ate an image directly onto the plate. Other than washout, no post-processing steps are required which could potentially have an adverse effect on the engraving. The ability to directly engrave elastomer and polymer plates with laser precision impacts all three dimensions of the image being reproduced on the printing plate. Plate room operators and prepress providers have the ability to shape shoulder angle, relief depth and below-surface images. Plate relief becomes more shallow and stable because the plate can be engraved in the third dimension. Direct engraving truly gives you the freedom to make the plate any way you desire. Shoulder Angle. DLE allows the user to manipulate shoulder angle to whatever specification is required. For the most part, today ’s shoulders are approximately 45 to 50 degrees on ana- log and/or CTP plates. With DLE, the shoulder angle can be just about anything desired. The average shoulder for direct laser engraving is 75 to 80 degrees in the highlight and 90 degrees in the shadow. Sharp shoulders produce sharp print. Relief Depth. This is similar to a back exposure with photo- polymer. An assigned depth is entered into the laser and it cuts the plate to that exact depth. Below-Surface Image. This is truly the greatest feature about DLE. The laser controls image height based on the pres- sure that is placed on the press. This pressure is key to three- dimensional engraving. You can experiment with a test plate using three or four different types of below-surface structures. Printing with the test plate will show the specific structure that is best suited for your engraving, based on pressure needed for each substrate. Once the test is complete, you will have every- thing you need to create a perfect kiss impression. DLE allows operators to place greater pressure wherever it is required (solids) and minimize pressure for highlights—all Direct Engraving a Flexographer’s Dream...Come True By paul Zeinert FigurE 1: Direct laser engraving (DlE) allows even greater control over dot height and shape. all art courtesy anderson & Vreeland. FigurE 2: Note the highlight dots have a 60 degree shoulder angle and shadow dots have a 90 degree angle. FigurE 3: Highlight dots can be placed below the surface to prevent over impression. • While the benefits of CTP are impressive, the technol- ogy only allows for the manipulation of an image in two dimensions. • DLE allows the user to manipulate shoulder angle to whatever specification is required. • The laser controls image height based on the pres- sure that is placed on the press. • With current software, creating an endless design is as simple as dragging an image into a template. TEchNologiEs & TEchNiquEs Toll-free Phone: 866.282.7697 Toll-free Fax: 800.223.6869 www.AndersonVreeland.com info@AndVre.com Most people know us for our flexo plates and equipment. But A&V is a lot more than flexo plates. Our extensive product line includes everything from anilox rolls to zahn cups. In between, we offer thousands of products, like densitometers, doctor blades, edge sealing tape, end seals, electrical tape, Epson printers and supplies... just to name a few. We also offer training and almost 50 years of flexo experience to support these products. Ask your A&V representative for a com- plete list of our products, or visit our web site and take full advantage of our complete product line. Because we are flexo, and a lot more. TM WE ARE See us at INFO*FLEX booth 513-519 AV9458 WeAreFlexo ad v2.indd 1 3/9/10 10:26:50 AM FLXApril10_mech.indd 28 4/10/10 1:22 AM
Sustainable Winter 2010