Anilox Engraving
Engravers can employ the same cutting-edge processes, such as laser engraving, on sleeves as they can with rolls.
April 2007 by Chris Mc Loone
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Flexographic printing’s gains in the market are unmistakable, and the quality of its end products continues to improve. Anilox rolls are a key component in the quality equation in flexo printing, and also in the equation for its productivity. Improving prepress operations for flexographic printing means, in part, improving efficiencies of anilox roll change-out and preparation. To a large degree, anilox roll preparation equates to engraving.
Anilox sleeves are enjoying increased usage in this arena, and some might be surprised that the sleeved alternative to engraved anilox rolls can sometimes exceed the LPI (lines per inch) of rolls. Plus anilox engravers can employ the same cutting-edge processes, such as laser engraving, on sleeves as they can with rolls. There are pluses and minuses to using rolls and sleeves or vice versa, many of which deal with volumes rather than the actual applications.
Engraving rolls and sleeves
Despite the type of anilox device you spec, the full gamut of engraving techniques is available, including laser engraving. The engraved surfaces, in general, are the same. “Most anilox sleeves have an outermost layer composed of metal, typically aluminum,” says David Lanska, midwest regional sales manager, Stork Cellramics. “This surface reacts to processing in a very similar fashion to a conventional steel core. Once overcoated with ceramic, the laser reacts the same to the sleeve or the roll.” He adds that once the sleeves are mounted on air cylinders, the processing steps are nearly identical for sleeves and conventional rolls.
According to Dave Burgess, vice president, sales and marketing, Pamarco Global Graphics, there are no differences in terms of engraving between sleeves and rolls. “They are both prepared for laser engraving by applying a heavy layer of chrome oxide ceramic, diamond grinding, and then diamond polishing,” he says.
Of note is sleeves’ sensitivity to temperature. Lanska states that the internal construction of the sleeves means temperature control is critical during the plasma coating operation, “to prevent degradation of the composite and compressible layers.” He also adds, “The materials typically used for sleeve construction do not stand up well to heat or caustic chemicals. Repeated exposure to these can cause the layers to break down and lead to catastrophic failure of the sleeve.”
Lloyd Dreger, technical director, Laserlife, adds that one must be careful in coating sleeves with ceramic because the thin aluminum layer is not sufficient to conduct away the heat generated in the process. “You also have plastic present, which cannot tolerate high temperature without deterioration,” he says.
Anilox sleeves are enjoying increased usage in this arena, and some might be surprised that the sleeved alternative to engraved anilox rolls can sometimes exceed the LPI (lines per inch) of rolls. Plus anilox engravers can employ the same cutting-edge processes, such as laser engraving, on sleeves as they can with rolls. There are pluses and minuses to using rolls and sleeves or vice versa, many of which deal with volumes rather than the actual applications.
Engraving rolls and sleeves
Despite the type of anilox device you spec, the full gamut of engraving techniques is available, including laser engraving. The engraved surfaces, in general, are the same. “Most anilox sleeves have an outermost layer composed of metal, typically aluminum,” says David Lanska, midwest regional sales manager, Stork Cellramics. “This surface reacts to processing in a very similar fashion to a conventional steel core. Once overcoated with ceramic, the laser reacts the same to the sleeve or the roll.” He adds that once the sleeves are mounted on air cylinders, the processing steps are nearly identical for sleeves and conventional rolls.
According to Dave Burgess, vice president, sales and marketing, Pamarco Global Graphics, there are no differences in terms of engraving between sleeves and rolls. “They are both prepared for laser engraving by applying a heavy layer of chrome oxide ceramic, diamond grinding, and then diamond polishing,” he says.
Of note is sleeves’ sensitivity to temperature. Lanska states that the internal construction of the sleeves means temperature control is critical during the plasma coating operation, “to prevent degradation of the composite and compressible layers.” He also adds, “The materials typically used for sleeve construction do not stand up well to heat or caustic chemicals. Repeated exposure to these can cause the layers to break down and lead to catastrophic failure of the sleeve.”
Lloyd Dreger, technical director, Laserlife, adds that one must be careful in coating sleeves with ceramic because the thin aluminum layer is not sufficient to conduct away the heat generated in the process. “You also have plastic present, which cannot tolerate high temperature without deterioration,” he says.
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