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.
The servomotors that drive the squeegee assembly are another hallmark of the newer generation of roll-to-roll presses. A servomotor drive is an automatic device that uses error-sensing feedback to improve performance. This electronic feedback on the squeegee positioning enables much greater precision in squeegee advance and thus the smaller gaps between first and second prints. Today’s systems can achieve a 1-mm gap between first and second prints. Earlier generation roll-to-roll flatbed systems used traditional motors to drive squeegees and could not achieve that standard.
High-tech inks and dryer controls
The recent proliferation of specialty inks is creating new capabilities for high-tech products such as printed circuits with precisely controlled electrical resistance characteristics. These new inks are also increasingly preferred for products that need to weather radiation and other environmental impacts. Handling these newer high-tech inks has called for the development of new technology, including electronically controlled contact-dryer technology (Figure 3) that is able to very precisely maintain proper temperature and air flow, which affect ink reactions.
For those not familiar with contact drying technology, it consists of an adjustable heated vacuum plate and conveyor carrying the material being dried combined with adjustable hot air from the top. In this type system, the wet ink dries from the substrate upward toward the print surface. Even for thick coated inks, drying times can be expected to be a fraction of that required in conventional heated oven systems. For example, a substrate that takes two hours to dry with traditional heated air methods now takes 30 sec.
With certain high-tech inks, there is a particle in the ink makeup that requires a very controlled temperature and air flow to properly cure. The ink reaction is not simply a process of drying, but rather an unfolding of a chemical reaction that requires strictly controlled environments to proceed as designed. The contact dryers are controlled electronically and can be set for the precise drying requirements of particular solvents and high-tech inks. In fact, the better systems also have feedback mechanisms that automatically shut the dryer off if and when solvent concentrations become dangerously high and potentially explosive.
Modular design principles are now firmly established for the latest generation of roll-to-roll screen-printing systems. This makes them flexible for adding multiple print stations, drying systems, diecutters, laminators, slitting and sheeting systems, or other modules as needs arise. This has allowed many screen-printing shops equipped with this newer technology to move into new markets more easily, because equipment is more readily adapted to new job requirements.
Moving into new markets is what the latest technological improvements are all about. Whether it’s lightweight airplane cabin interior panels, RFID components, transfers for industrial textiles, printed luminescent faceplates, or intricate membrane-switch designs, the proliferation of modern uses for screen-printing technology continues. Many of the products made with the latest generation of web screen-printing systems simply did not exist a decade ago. Many of those who design and build screen-printing equipment now devote considerable R&D resources to keeping pace with these changing market requirements.
Get business rolling
Roll-to-roll screen-printing systems are now the best fit technology for high-volume production of many screen-printed products for automotive and electronics industry applications, and especially those using the newer high-tech inks. Since such products are likely to become a larger part of the specialty graphics market, now is a good time to pay attention to the developments in roll-to-roll technology and what it could mean for your company.
Reinhard Zimmermann is general manager of Systec and a director of the Spartanics-Systec partnership, which manufactures Spartanics-Systec Fineprint Screen Printing Systems. He can be reached by e-mailing zimmermann@spar tanics.com. More information about the Spartanics-Systec partnership is available at www.spartanics.com.
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