UV LED curing systems are no longer just a concept in the label and packaging printing industry. The technology is seeing significant adoption throughout converting facilities, and with good reason.

The US market’s transition to LED remains slower than other places in the world, but the number is still growing. For example, LED system manufacturing has now reached over 50% of GEW’s production. Markets remaining with mercury tend to do so for costs reasons.

While cost is an initial issue, R&D is taking place on a daily basis to alleviate these concerns.

“Understandably, the most common requests are centered around ways to make the UV curing process faster, better, and cheaper for our customers,” explains Amir Dekel, vice president of sales. “Speaking for GEW, we are really achieving that through our latest product introductions. We invest hugely in innovation and R&D each year, which enables us to consistently introduce essential new products that improve productivity and profitability for converters. And on that note, I know that we have some amazing new technological developments to introduce to the market later this year, after more than two years of research and development. It’s very exciting.”

LED trending

The trend within UV LED curing technology itself is toward the development of ever more powerful, more efficient and more reliable LED arrays. As an example, GEW’s AeroLED2 model now delivers over 30% more electrical power, over 30% extra UV dose, and over 40% more UV irradiance than its predecessor model, AeroLED.

“To put this into context, this level of improved efficiency was achieved in a little under two years, and this continual development goes on,” says Dekel. “Air-cooled AeroLED2 is now available for web widths up to 70cm and is therefore suitable for the vast majority of label and narrow web applications.”

For the highest performance applications, such as low migration labeling and flexible packaging, GEW has also developed its highest power, water-cooled UV LED model, LeoLED2. This latest product has also evolved to deliver more power (up to 147W/cm), higher irradiance (44W/cm²), and a higher dose (300mJ/cm²). This power level is now comparable with conventional UV, making LED a viable solution for a much broader range of applications than ever before, Dekel notes. There is still room for improvement, though.

“We see industry adoption of LED gathering pace day by day, month by month,” remarks Dekel. “However, there are certain processes and applications that are not yet truly ready for UV LED, such as certain coatings, varnishes, and special colors. While these are either prohibitively expensive or just plainly unavailable in LED-compatible form, GEW can offer the perfect solution for label and web printers, which we refer to as ArcLED. This patented, interchangeable technology enables UV LED and conventional UV Arc lamps to be run side by side on a press, for ultimate flexibility.

Solving challenges

The evolutions of other print technologies, such as faster press speeds, has created the need for curing advancements. These challenges are being met with more effective and efficient LED lamps, states GEW. According to Dekel, in situations where particularly high performance is required, the curing process can be further enhanced with GEW’s state-of-the-art inert gas solution, OxyGuard.

“OxyGuard is GEW’s next generation oxygen control system, which rapidly achieves and maintains the optimal curing atmosphere for low odor, low migration production, siliconization and other high performance curing applications,” states Dekel.

OxyGuard features closed loop control, which automatically maintains this oxygen level to a customer set point (measured in parts per million), and ensures this set point is not exceeded. The OxyGuard system adapts the input of inert gas accordingly, regardless of machine running speed. Throughout the process, gas consumption is optimized for maximum efficiency.

“When talking about speed, there is no longer any need to slow the press for the sake of the curing process,” adds Dekel. “In fact, utilizing the OxyGuard technology, today we can cure inks faster than most narrow web presses can run.”

Sustainable benefits

The switch to LED curing brings with it a host of sustainability advantages. First and foremost, energy consumption is dramatically reduced. The higher electrical efficiency of LEDs and purity of UV output allow typical energy savings of over 60%, compared to a mercury UV system of similar specification.

“A further energy saving is achieved with LED as a result of instant on/off switching,” says Dekel. “LEDs are immediately ready to use from the moment they are switched on. There is no warm-up or cool-down cycle, as is the case with conventional Arc lamps. Unlike Arc curing, the UV LED process does not produce any ozone as a by-product and there are no air extraction requirements (other than air extraction to keep the lamps cool). LED also eliminates the need for mercury Arc lamps.”

While it is recommended to replace conventional mercury Arc bulbs every 1,000 hours, GEW’s LED diodes have a life expectancy of up to 40,000 hours, dependent on the model, GEW notes. This results in a greater reduction of consumables.

“As LED curing generates a fraction of the heat that the conventional UV process does, energy consumption can be further decreased by reducing the need for heat management in the workplace,” comments Dekel.