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 : August 2011
www.flexography.org august 2011 FLEXO 45 single product—say a trash bag displaying nothing more than a printed logo. That observation, as well as others, is shared by Marco Verini, technical services manager for Uteco North America. He maintains that, “The stack gives great flexibility to print front/back combinations, which is very useful when printing on tubing (mulch, insulated bags, etc.). Other benefits offered: up to a 50-in. repeat and 94-in web width. Also of note, according to Verini, “In-line stack presses can be equipped with high capacity dryers, similar to gravure. “ Furthermore, “Stack presses are a smaller investment than the higher-end central impression (CI) printing presses, and provide reliable quality at moderate speeds.” FORMAT & APPLICATIONS Flexographic Technical Association’s Flexography: Prin- ciples & Practices, 6th Edition, describes the format and its technical applications. “ In the stack press individual color stations (sometimes called sections or decks) are stacked one over the other, on one or both sides of a main press frame. Each color station is driven through either servo motors or traditional gear trains supported by the main press frame. Stack presses have three main advantages”, as FTA explains: • First, the operator can usually reverse the web to allow both sides to be printed during one pass through the press. Various web threading arrange- ments allow complete ink drying before the reverse side is printed, provided enough drying capacity is designed into the area where the web passes between the two series of stations. • Second, color-station accessibility facilitates changeover, wash-up, etc. • Third, the press can print large repeats. Technical experts working on behalf of the association also write, “The stack press has proved useful in many applica- tions and has been used to print on almost every type of substrate.” T hey admit, “It does have limitations when printing substrates that are extensible or of extremely thin gauges, generally restricted to color registrations.” That said, they also note, “When heavier gauge materials are being printed, such as papers, laminated film structures and others that can tolerate fairly high web tension values, the stack press can profitably produce commercially acceptable registered products. The stack press lends itself well to ap- plications such as printing in-line with other types of machin- ery. These add-ons may include extruders, bag machines, sheeters, laminators or other equipment.” top: uteco’s Emerald, Onyx stack in-line presses, along with the more basic gold and gold roll-to- roll stack models.