GEWA Etiketten – A World First in digital prepress for adhesive labels
Midway through 2009, GEWA Etiketten GmbH switched its prepress for self-adhesive labels from the conventional process with films to CtP exposure. This made them the worlds‘ first printing company to expose letterpress, flexographic, offset plates, and Gallus Screeny printing plates on a single CtP output unit – the Lüscher XPose! 230 4FLEX.
GEWA is a leading manufacturer of Premium Quality high-finish and self-adhesive labels for the wine and spirits industry. Based in Bingen am Rhein, GEWA employs around 165 staff across two production sites, with their second facility located in Gau-Bickelheim. The workforce at the Bingen headquarter is no stranger to CtP, having introduced automated CtP plate exposure back in 2006, producing 3 different plate formats for all high quality labels on their state-of-the-art offset presses.
Sophisticated self-adhesive labels
In addition to self-adhesive labels, the facility in Gau-Bickelheim also produces pre-printed labels – another key component of the business. It has five Gallus narrow-web presses operating over three shifts, and these hybrid presses combine offset, flexographic and screen printing with embossing, die-cutting and hot/cold-foil finishing processes. For over-printing work, a Quickmaster from Heidelberg, a two-colour GTO and a two-colour Ryobi offset press are joined by twelve Tiegel presses from Heidelberg and five LeoMat Overprinters. All these presses require a variety of different printing plates (letterpress, flexographic, offset plates, and Gallus Screeny‘s for screen printing). Before the Lüscher XPose! 4FLEX revolutionised their production, the repro films for all these processes were produced in-house and copied in the conventional way in the prepress department. The head of this department, Oliver Jung, explained how this entailed making plates and screens in 25 different formats!
You could be forgiven for thinking that, 15 years after Computer-to-Plate technology was introduced, conventional plate production is out of date and its quality needs to be improved. However, GEWA Etiketten proved that this was not the case in 2008 when it won the German Printing Industry Innovation Award for its Fürst von Metternich Rosé label. The label was printed in a single pass using a combination of hot foil, screen printing, Euroscale and gold cold foil. The relief coating applied at the end using screen printing gives texture to the medallion for a sophisticated label finish.
The company had continued to make plates in the conventional way for such a long time because at least three different CtP systems would have been needed for digital plate production! However, following in-depth research into GEWA‘s options and numerous tests involving a number of potential suppliers, GEWA Etiketten established that the Lüscher XPose! 230 4FLEX was the best choice for their wide range of plate formats and needs.
Good experiences with five plate types
So the world‘s first Lüscher XPose! 230 4FLEX started operation in Gau-Bickelheim in June 2009, and is used for producing all plates for the site. In addition, the system‘s exposure format extends to 1130 x 950 mm – so it also serves as a back-up for conventional offset plates in Bingen. For the 25 different smaller plate formats in Gau-Bickelheim, lines were marked and labelled in the drum so that any employee can insert the plates correctly before the Lüscher XPose! 230 4FLEX holds them securely with a vacuum during exposure.
GEWA actually exposes five different types of plates:
The hard, steel-backed letterpress plates are pre-coated with a black ablation (LAMS) layer. The image is made on the plate by the machine‘s inbuilt 940nm thermal diodes which vaporise the black layer. The plates are then cured with UV light as before and subsequently washed out, dried and post-exposed automatically.
As with letterpress plates, thermal diodes are used to expose the LAMS layer of the softer flexographic plates. Here too, the plates are subsequently dealt with in a similar way to Letterpress.
Conventional Gallus Screeny plates are used for screen printing. The Screeny material comes pre-coated with a photopolymer layer and the non-printing parts are exposed using the machine‘s inbuilt 405nm UV diodes. The screen is then washed out and mounted on rings in the usual way, ready for mounting onto the press, and the tried-and-tested printing processes remain unchanged. Thanks to the UV laser diodes in the Lüscher, it is possible to image state-of-the-art screen printing plates “digitally” (Screeny Standard and Screeny S-Line) and extremely quickly. Obviously, XPose! 4FLEX eliminates the costs and additional steps previously required with analogue film, and also removes the reliance on film totally, which is rapidly declining in availability.
Formerly the Agfa Zenith negative plate was used. But just this plate initially caused as the only of these four plate types problems on the XPose! 230 4FLEX, as they proved to be very insensitive and the exposures according to format lasted too long. To this date, however, Agfa had already developed the plate to Aluva N, which lets expose without any difficulty and is used successfully since then.
700 x 770 mm flexographic coating plates that can be washed out with water are exposed on the XPose! 230 4FLEX and then developed and produced in a wash-out tower for the Heidelberg XL75 in Bingen.
The switch-over from conventional film exposure to the Lüscher XPose! 230 4FLEX went very smoothly. Head of department, Oliver Jung, did a lot of preparatory work to set up a new plate-making workflow. Instead of films, all jobs are sent from Bingen as 1-bit TIFF files to join the queue on the XPose! control computer 20 kilometres away.
To expose plates, an operator decides which plate type and format is to be exposed and prepares the necessary plates. For registration of Gallus Screeny material, pneumatic registration pins pop out of the drum for easy positioning. Once exposed, the operator simply removes the exposed plate, inserting a new one and initiating the exposure by pressing a convenient footswitch. Depending on the material being exposed, the machine will either use UV lasers or Thermal (UV lasers expose screen and offset plates / Thermal lasers expose flexographic, letterpress and coating plates). Changing the light source is done at the press of a button. Thanks to the plate-edge and focus sensors incorporated in the system, no further adjustments are required and the next plates can be inserted and exposed.
GEWA has installed a machine with 16 laser diodes each for thermal and UV exposure but if necessary, the XPose! can easily be upgraded to 32 laser diodes in future to accommodate larger plate volumes. “We established that two employees per shift do the manual required operations along-side the exposure time at a good, constant pace of work,“ comments Oliver Jung. “If we upgraded the machine to expose twice as fast, we couldn’t do the manual work faster, so the gained exposure time would not be transformed into higher production!“
Technical director Uwe Refflinghaus decided to digitise all plate-making processes in Gau-Bickelheim more than a year ago and he reflects that it has been both successful and cost-effective: “The XPose! 230 4FLEX is the best solution for our facility and exposes the wide range of formes of Screeny, Flexo, Letterpress and Offset printing plates used in day-to-day production both reliably and flexibly”.