Greg Hrinya, Editor05.01.24
With label converters looking for ways to improve their bottom line and lower their carbon footprint, LED curing has emerged as a viable technology. Suppliers have worked tirelessly to optimize this converting technology, and the substantial enhancements to LED curing have been making their mark at label printers’ facilities across the globe.
Both conventional UV and UV LED curing systems are far more efficient today than they were a decade ago. This means newer systems require less electrical power to produce the same UV output as older systems. This results in immediate energy savings to label printers following an upgrade of an older UV system or after installing a new UV press.
When comparing conventional curing technologies to LED, the latter offers a host of benefits. “When compared to conventional UV systems, LED is better at curing inks, especially white inks and densely pigmented inks,” explains Jennifer Heathcote, VP of business development, GEW (EC) Limited. “LED is also better at curing laminating adhesives, cold foil adhesives, cast and cure coatings, and thicker formulation laydowns. LED’s longer UVA wavelengths penetrate deeper into formulations, pass more easily through films and foils, and are less absorbed by color generating pigments. This means more energy goes into the chemical reaction to facilitate better opacity, better cure, and faster line speeds. From a process perspective, UV LED is more efficient.”
UV LED systems also turn on and off instantly. This eliminates the warm-up, standby, and cool-down states associated with conventional UV systems. This saves valuable production time and energy. UV LED lampheads have long lifetimes and utilize no lamps, reflectors, or shutter mechanisms, which reduces maintenance and eliminates consumables.
Plus, UV LEDs do not emit heat generating infrared wavelengths or produce ozone. With LED, converters can run more thermally sensitive substrates and reduce wear and tear on the press. Because there is no ozone, there is no need for roof penetration and no conditioned make-up air for an all-LED system, which reduces both operating costs and capital equipment expenditures.
“UV LED output is consistent over the life of the product, whereas arc lamp output begins to degrade from first strike,” notes Heathcote. “With UV LED, label printers are more confident in cure quality when running the same job months apart. Due to the lack of lamps, reflectors, and shutters, there is less maintenance, which means less trouble shooting and less variability in output due to component degradation. All of this means that UV LED increases the robustness of the printing process.
“For many years, the cost of an LED system exceeded the cost of an arc lamp system,” adds Heathcote. “This is no longer the case for many configurations and is the reason many printers are quickly transitioning to LED curing.”
According to GEW, it is possible to achieve 70% energy savings with GEW’s AeroLED powered with 53 Watts Per Centimeter (WPC) compared to the company’s conventional E2C powered with 140 WPC. The reduction in supply power leads to a financial benefit of tens of thousands of dollars annually. For many retrofits, this is enough to create appealing ROIs with less than two-year paybacks.
“Consider an 8-station, flexo press running 47 cm lamps for two 8-hour shifts over 312 days of annual operation,” says Heathcote. “Based on 60% press utilization and a $0.10 per kWh electricity rate, the annual energy savings is 142,500 kWh. The value of that savings is $24,000 USD, and the CO2 saved is 58 metric tons.
“UV LED curing systems reduce the total power required from the plant transformer,” Heathcote continues. “This means that printers can run more lines off an existing transformer and can often avoid installing a new transformer when expanding printing capacity. UV LED curing systems lower peak demand at start-up and reduce energy consumption during operation. For many facilities, high peak demand charges can be responsible for as much as 40% of the electricity bill. As a result, lowering peak demand has a significant impact on electricity bills. UV LED curing has zero Scope 1 emissions and reduces Scope 2 emissions. This is fantastic for the bottom line and directly impacts the sustainability efforts of the organization.
“UV LED curing means that there are no greenhouse gases (GHGs), volatile organic compounds (VOCs), hazardous air pollutants (HAPs), or toxic air pollutants (TAPs) emitted by the label printer to the atmosphere. This is beneficial as climate change and air quality regulations are increasingly targeting plant emissions. UV LED systems also eliminate the use of mercury. By comparison, a small amount of mercury is contained inside the quartz tube of an arc lamp system,” she concludes.
Many of the formulations that printers use today are already dual cure, meaning the inks work with both conventional UV and UV LED curing systems. As a result, once the UV system is upgraded to LED, typically something which can be done by a service technician within a 72-hour window, label printers are able to seamlessly jump right back into production.
“Label printers are generally surprised at how easy the transition is from conventional mercury vapor to LED,” comments Heathcote. “Many tell us that they wish they would have made the transition sooner.”
Both conventional UV and UV LED curing systems are far more efficient today than they were a decade ago. This means newer systems require less electrical power to produce the same UV output as older systems. This results in immediate energy savings to label printers following an upgrade of an older UV system or after installing a new UV press.
When comparing conventional curing technologies to LED, the latter offers a host of benefits. “When compared to conventional UV systems, LED is better at curing inks, especially white inks and densely pigmented inks,” explains Jennifer Heathcote, VP of business development, GEW (EC) Limited. “LED is also better at curing laminating adhesives, cold foil adhesives, cast and cure coatings, and thicker formulation laydowns. LED’s longer UVA wavelengths penetrate deeper into formulations, pass more easily through films and foils, and are less absorbed by color generating pigments. This means more energy goes into the chemical reaction to facilitate better opacity, better cure, and faster line speeds. From a process perspective, UV LED is more efficient.”
UV LED systems also turn on and off instantly. This eliminates the warm-up, standby, and cool-down states associated with conventional UV systems. This saves valuable production time and energy. UV LED lampheads have long lifetimes and utilize no lamps, reflectors, or shutter mechanisms, which reduces maintenance and eliminates consumables.
Plus, UV LEDs do not emit heat generating infrared wavelengths or produce ozone. With LED, converters can run more thermally sensitive substrates and reduce wear and tear on the press. Because there is no ozone, there is no need for roof penetration and no conditioned make-up air for an all-LED system, which reduces both operating costs and capital equipment expenditures.
“UV LED output is consistent over the life of the product, whereas arc lamp output begins to degrade from first strike,” notes Heathcote. “With UV LED, label printers are more confident in cure quality when running the same job months apart. Due to the lack of lamps, reflectors, and shutters, there is less maintenance, which means less trouble shooting and less variability in output due to component degradation. All of this means that UV LED increases the robustness of the printing process.
“For many years, the cost of an LED system exceeded the cost of an arc lamp system,” adds Heathcote. “This is no longer the case for many configurations and is the reason many printers are quickly transitioning to LED curing.”
According to GEW, it is possible to achieve 70% energy savings with GEW’s AeroLED powered with 53 Watts Per Centimeter (WPC) compared to the company’s conventional E2C powered with 140 WPC. The reduction in supply power leads to a financial benefit of tens of thousands of dollars annually. For many retrofits, this is enough to create appealing ROIs with less than two-year paybacks.
“Consider an 8-station, flexo press running 47 cm lamps for two 8-hour shifts over 312 days of annual operation,” says Heathcote. “Based on 60% press utilization and a $0.10 per kWh electricity rate, the annual energy savings is 142,500 kWh. The value of that savings is $24,000 USD, and the CO2 saved is 58 metric tons.
“UV LED curing systems reduce the total power required from the plant transformer,” Heathcote continues. “This means that printers can run more lines off an existing transformer and can often avoid installing a new transformer when expanding printing capacity. UV LED curing systems lower peak demand at start-up and reduce energy consumption during operation. For many facilities, high peak demand charges can be responsible for as much as 40% of the electricity bill. As a result, lowering peak demand has a significant impact on electricity bills. UV LED curing has zero Scope 1 emissions and reduces Scope 2 emissions. This is fantastic for the bottom line and directly impacts the sustainability efforts of the organization.
“UV LED curing means that there are no greenhouse gases (GHGs), volatile organic compounds (VOCs), hazardous air pollutants (HAPs), or toxic air pollutants (TAPs) emitted by the label printer to the atmosphere. This is beneficial as climate change and air quality regulations are increasingly targeting plant emissions. UV LED systems also eliminate the use of mercury. By comparison, a small amount of mercury is contained inside the quartz tube of an arc lamp system,” she concludes.
Many of the formulations that printers use today are already dual cure, meaning the inks work with both conventional UV and UV LED curing systems. As a result, once the UV system is upgraded to LED, typically something which can be done by a service technician within a 72-hour window, label printers are able to seamlessly jump right back into production.
“Label printers are generally surprised at how easy the transition is from conventional mercury vapor to LED,” comments Heathcote. “Many tell us that they wish they would have made the transition sooner.”