A thoroughly modern cure

20 January 2011



The demand for high efficiency curing systems that fall inline with today’s price conscious market continues to grow apace. Nick Coombes highlights some current trends and developments.


According to Simon Mitchell, Managing Director of IST (UK), the market for UV technology is showing clear signs of improvement, with a number of new enquiries and projects. The company’s latest technology for a 140W/cm system has the potential to save more than €5,000/year, compared with existing systems, says Mr Mitchell: “These are significant savings and are often overlooked when companies try to reduce costs. They see only the bigger picture, and fail to appreciate that each element in the production process is a cost factor.”

He adds: “Reducing energy consumption has become a key issue for many flexo and label printers and if this can be achieved it results in lower production costs providing improved competitiveness. Lower energy consumption is also beneficial to the environment as it reduces carbon emission and helps to counter environmental measures such as carbon tax.”

When it comes to the running of UV curing systems there has been a responsible approach to the ever-increasing energy costs from most manufacturers. For example, IST’s MBS-5 curing system, which is typically aimed at the flexo and narrow web market, incorporates a number of innovative features said to make significant savings in energy consumption without compromising the speed or quality of cure.

The key is the new URS cold mirror reflector, which optimises UV reflection so that a higher amount of UV is reflected onto the substrate. This increases yield and reduces any UV being misdirected. The reflector’s ‘wraparound the lamp’ feature allows it to capture more of the UV energy which, combined with its greater reflectivity, ensures substantial cost savings through reduced energy consumption. This new technology maximises the UV yield so that a system using a lamp of 140W/cm will give UV curing capacity of 160W/cm or even 200W/cm, without slowing the press.

Further energy savings are available with today’s new power supply units, which typically have an efficiency rating above 95% and are infinitely adjustable. With standby power requirements down from 50% to around 20%, lamp output is automatically minimised in standby mode. This reduces power consumption and prolongs lamp life. Even lamp technology has moved on to create cost control. Modern systems allow for lamp changes in less than one minute. On a 10-colour press this can reduce print downtime by around two hours.

The improving market view is corroborated by Albert Manser of Mathis (Switzerland), who adds: “We see that demand from Asia appears to be running ahead of the developed markets of Europe“. He agrees that speed, energy efficiency, and cost reduction, are the main drivers keeping R&D departments busy. Mathis is involved quite heavily with the development of pilot and lab test equipment, which is a mark of how much detailed investigation goes into print curing today as end users strive to achieve the superiority that increases market share.

One instance cited by Mr Manser was a special project for a customer who wanted to apply a controlled amount of dispersion varnish with variable coating width and minimum solvent evaporation. Mathis designed a special trough that is adjustable for various widths and incorporates automatic filling and emptying as well as a level sensor. “This is typical of the work we are being asked to undertake,” he says.

At UK-based GEW, the latest generation of its e-System with e-Brick power supplies, is designd to increase energy efficiency. Users can select the power level required based on the properties of the ink, coating or adhesive at the appropriate press speed.

“The tendency has been to use full power to combat the risk of under-cure,” says Brian Wenger, President of GEW’s USA operation. “Our aim is to reduce energy costs and prevent spoiled print jobs by using the minimum power required to cure, with extra in reserve for the more difficult jobs.”

The company is also working on new technology that will be effective on heat-sensitive substrates, such as the many filmic materials now used in label conversion. These pose a particular problem with distortion in both x and y direction, which creates problems in down line processing. With the recent growth of the ‘no-label’ look, in-mould labels and shrink sleeve labels, production demands have increased greatly. This, combined with the well-proven benefit of UV cured inks and coatings, has brought new solutions. Since 60% of the output of a UV lamp is heat, one can appreciate the problem with thermo-sensitive materials.

GEW’s new VCP Film UV curing system incorporates an integral water cooled chill roll positioned opposite the UV curing lamp, which eliminates the effects of heat on the substrate. Usefully, this new technology is available as a retrofit. All that is needed is hosing and a modest refrigeration unit, which makes this a low cost upgrade, and allows the customer to enter new markets, according to GEW.

Demand is also growing for UV curing on wider web, central impression presses in the flexible packaging industry, where the benefits and quality of UV flexo on films traditionally printed with solvent based inks is being recognised. There are now installations in Europe on 800mm wide presses where the provision of a water-cooled solution is enabling flexo printers to compete in the high quality gravure market.

Moving away from UV technology, Lawrence Wild of Edlon Machinery, the UK agent for American manufacturer Energy Sciences International (ESI), explains how electron beam (EB) curing, together with the WetFlex process, developed by Sun Chemical, is combining high quality with eco-friendly emissions.

The inks are applied wet-on-wet to the substrate with no inter-colour drying - just one EB unit at the end. According to Mr Wild: “Compared to conventional systems that use solvent or water-based inks, WetFlex allows for a much higher resolution of the graphics.” This is due to finer plate screens and anilox rolls and a more homogeneous dot structure. “In addition to the high resolution capability, it’s the excellent ‘trapping’ behaviour, the brilliance and high gloss, the density stability and scuff and abrasion resistance of the cured ink that ensures high quality flexo printing graphics,” he adds.

The process is suitable for extended gamut printing, where five, six, seven and more standardised colours are used to create a broad range. This offers a significant reduction in changeover times and avoids left-over or waste ink. Compared to conventional flexo presses, there are no dryers and no thermal oxidation systems or similar VOC abatement. And there are no CO2 emissions at all, and no ozone is produced.

Mr Wild concludes: “With EB processing you meet all environmental protection requirements with the lowest possible energy use, and can avoid or reduce any future energy consumption taxes. Now, that must be worth looking at!”


The new URS Reflector has a wraparound profile for higher efficiency. URS New lamp technology. New lamp Latest reflector technology. Latest reflector Mathis is heavily involved in pilot and lab test system manufacture. Mathis EZCure electron beam system fitted to a Muller-Martini press. EZCure

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