German label converter Rako uses AVT systems on its LeoMat rewinders
Since its foundation in 1969 by Ralph Koopmann, German based label converting specialist Rako Etiketten has acquired a reputation for its enthusiastic and ready acceptance of new technology.
In 1997 it was the first printing house in Germany to commission an Indigo Omnius-Digital press for printing labels, foil and cartonboard in top quality offset. The resulting growth in demand for digital offset printing led to the acquisition of another two presses for printing six colour Indichrome and a fourth machine, an Indigo Omnius Webstream 100, was installed in May, 2002.
With the latest acquisition, a PrintVision Helios 100 per cent quality assurance solution from Advanced Vision Technology (AVT), Rako claims to have maintained its record of being the first to adopt a new technique.
Rako’s production facilities in Witzhave, Hamburg, house a “clinically” clean, printing hall, and an array of 30 presses. A tablet above each press gives details of its configuration, printing process and ancillary equipment, while another bears the names of the crew.
Sascha Willhöft, who is responsible for data processing and organization, explains the reasoning behind the decision to acquire the Helios quality assurance system. “We wanted to have absolute quality control on the one hand, with the possibility of removing any faulty labels and replacing them with good ones on the other. We must deliver perfect reels to the customers to ensure trouble-free operation during the subsequent automatic labelling process. Having decided that we wanted the Helios, the question was: ‘Where to mount it?’ Not on press. We couldn’t stop and start the press, the downtime is too expensive and, anyway we have 30 presses to consider. Equipping each one would be an expensive exercise. And so, working in conjunction with the people from our LeoMat Maschinenbau (Machinery Construction) division, AVT’s technicians installed the Helios on an off-line LeoMat rewinder, thereby enabling us to gain experience with the control equipment in the most economical manner.
“We began using the Helios to control the quality of pharmaceutical jobs because that is the most critical sector; the text and symbols on the labels must be absolutely correct, complete and legible. Nothing must be missed or distorted. A comma, for example, must be printed as a comma and not a full stop. Now we are also using it to control top quality jobs involving branded articles from other customers.”
In operation, the Helios scanning head examines the full width of the running web while coloured lights indicate the state of the labels being scanned: green for faultless, yellow for slightly faulty ones and red for those with imperfections. On detecting a faulty label, signals from the head automatically stop the rewinder. The label in question can then be inspected on the screen of the control’s terminal to determine the nature of the flaw and whether the label should be removed and replaced with a good one.
Apart from ensuring that the printed images are complete and correct, the equipment detects a multitude of random defects such as misregistration, colour variations, streaking, spotting, hazing and misprints. It also ascertains that the matrix removal and die cutting processes are being performed accurately. The thresholds, at which the Helios activates the ‘fault’ signal for any of those defects, are preset on the terminal screen.
Rako ordered two more systems to equip other LeoMat rewinders. One of the new installations will incorporate an add-on module, which will enable the company to control the full colour surface of any kind of printed label. With the aid of a reflector support, the range of labels inspected will be extended to include those printed on all types of highly reflective substrates such as aluminium foil, metallized and transparent materials.
Some time ago, when trying to source a rewinder, Rako was unable to find one that met the specification. It decided to build its own in Witzhave. Since then, LeoMat Maschinenbau has manufactured all the rewinders required by Rako Etiketten, including 12 in the finishing department alone, and sold around 150 more.
In the digital printing department, LeoMats are used for die cutting and slitting reels of the labels printed on the Indigo Webmaster and also for overprinting using flexo and silk screen printing stations, which like the other finishing units can easily be interchanged as required. During overprinting and die cutting, accurate register is maintained by Insetter electronic controls, the scanning heads for which are mounted over the web on the stations concerned. The heads generate signals from which the state of the register is electronically determined; any misregister being automatically corrected by adjusting the speed of the station’s individual servo drive motors in order to alter the web tension and thereby the repeat length. Although the rewinders can run at speeds of up to 250m/min that is reduced to 120m/min when insetting is involved.
Peer Gronkowsky, of LeoMat, says they are capable of handling webs up to 510mm wide. In addition to the finishing functions, they can also be equipped with laminating, ink jet printing, hotfoil stamping and corona treating stations he adds. While at Rako they work in conjunction with Nilpeter presses, they can be employed off-line with machines from other manufacturers, such as Arsoma and Gallus.
In the main printing department 30 plus narrow web presses produce tags, tickets and special items as well as self adhesive labels. The machines are configured with up to 12 flexo, screen, offset or letterpress printing units which are combined in some cases to form hybrids, such as flexo and screen or offset with the flexo and screen processes. A wide variety of substrates are printed, ranging from films (PE, PP, PET and acetate) through adhesive papers (matt, high gloss pharmaceuticals), up to 300g/m2 cartonboard, using water based, UV, luminous, rub-off, thermal and scented inks.
Print run lengths extend from 1,000 to many million impressions. While short run, mono colour jobs are produced on a single colour Nilpeter press, depending on the image content, multi coloured ones are printed on one of the Indigos in the digital printing department. Due to the proportions of short run work, job change-overs average eight a day per press, but the downtime is kept to a minimum by fast makeready facilities.
Using the LabelManagement internet link, customers can view drafts of their graphics on-screen, discuss alterations and finally approve their jobs electronically.
The Rako Etiketten group employs over 500 people at its headquarters in Witzhave and other locations. Members of the group include the Hologram Company, which produces holograms for security purposes as well as sales promotions. The holograms are available in the form of self adhesive closing seals, tags, tear-off and safety strips for tickets and documents, metallic or transparent sleeves and packaging film. They can incorporate overt as well as covert, machine-legible data in addition to laser engraved serial numbering and barcodes.
Rako Security-Label specializes in producing electromagnetic and radio frequency (RFID) labels for protecting articles against theft, and Rako Pharma-Print, located in ‘clean-area’ production premises, produces labels, packaging and leaflets for the pharmaceutical industry.
About 20 per cent of Rako Etiketten’s production is exported directly and much of the rest goes abroad on customers’ products. The company’s international presence was extended in 2001 with new marketing and production subsidiaries in France and Croatia.
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