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Winding Up Productivity with Roll-to-Roll Screen-Printing Technology

(July 2008) posted on Thu Jul 03, 2008

Advanced digital control systems, improved engineering, and better material-handling technology characterize the latest generation of automated screen-printing systems for wide-format web substrates. Learn about the ease of operation, precision, and high throughput they can deliver in industrial and electronics printing environments.


By Reinhard Zimmermann

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Larger press sizes also create the need for more sophisticated methods of controlling how material is held and advanced through the systems. High-end roll-to-roll flatbed printing systems now feature an automated and synchronized vacuum release on the printing table that is especially important to speeding the throughput of large-format jobs. On cylinder roll-fed machines, tension of the substrate on the cylinder also is controlled via vacuum.

Use of vacuum for material positioning has a clear advantage in helping to deliver a scratch-free product. Indeed, if you are printing any length over 400 cm, using a vacuum positioning method to secure material has proven to be the only successful method. On flatbed machines, the use of synchronized vacuum release means that as the squeegee leaves a section the vacuum is released such that the transport system is able to pull on the material. If one does not release the vacuum in sections in this manner, there is a considerable reduction of throughput. Here too, it is the ability of the PLC electronic controls to precisely coordinate the squeegee advance and the vacuum release that makes this throughput efficiency possible.

 

Electronic controls and quality

In a simple screen-printing system, one needs to put pre-printed material in position on a printing table and then search for points of alignment and make manual adjustments before printing the next element. This is not only inefficient, but also relatively inexact compared to the precise positioning capabilities of the newer generation electronically controlled roll-to-roll systems. These systems have advanced algorithms in the software controls that can not only precisely register the material positioning but also can automatically compensate for screen stretch. The days of operators needing to look at every single print are a thing of the past. The quality advantage even enables these systems to handle the very high precision requirements of security products, such as holographs. Here too, it means that far less skilled operators are able to run a job and that the throughput advantage is considerable.


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