How to choose UV lights?

High-intensity electronic ultraviolet (UV) light is used in the solventless, high-speed photochemical process known as UV curing to polymerize inks, coatings, adhesives, and other photo-reactive materials into immediately fixed-in-place solids. In contrast, "drying" solidifies chemistry by absorbing, oxidizing, or evaporating it. When UV curing is used, the cured materials cling firmly to the substrate they were applied to and have a sufficient depth of cure without becoming tacky, sticky, or flakey.

Spot curing, flood curing, hand-held curing, and conveyor curing are among the UV curing types. A range of lamps are used as UV light sources in UV curing systems, including light emitting diodes (LEDs) that solely output UVA energy and mercury-based arc lamps that provide broad spectrum UV light. Although UVC LEDs can be used, their efficiency and power output are significantly lower.

A semiconductor device known as a light-emitting diode (LED) releases light when electricity passes through it. LED technology may be utilized for curing in an efficient manner when it is set to the UV spectrum. Find out more about LED UV Curing here.

The first UV curing apparatus, mercury arc (HG type) lamps, are used extensively as printing and other industrial production process solutions. Despite their effectiveness, they have drawbacks. Most importantly, they use a lot of energy and produce a lot of heat. In order to preserve the purity of the air, exhaust systems are necessary since they also create ozone. Mercury-arc bulbs have a long-term environmental effect and need to be disposed of at a cost and under regulatory monitoring. The average lifespan of a mercury-arc UV lamp, or bulb, is 1,500 hours.

LED-based UV curing addresses many of the issues with heat-set drying while offering all the benefits of conventional UV curing. These include minimal heat emission, quick and consistent drying and curing, immediate on/off, and low power usage. Furthermore, the tiny form factor of LED UV makes it perfect for integration into machinery or processes with little space. On average, LEDs endure about 20,000 hours.

Low heat emission, low power consumption, quick and consistent drying and curing, instantaneous on/off, and tiny form factor.

Shorter irradiation distances between the lamphead and substrate, limited irradiation intensity, and inability to generate short-wave UV light.

No, mercury lamps have surface temperatures higher than 750°F (398°C), while LED UV lamps have surface temperatures between 122°F and 140°F (50°C and 60°C). Heat-sensitive items are shielded from harm during the curing process by the low operating temperature of LED UV.

With an average lifespan of 20,000 hours, LED UV lamps are ten times more durable than arc UV curing lamps, which typically have a lifespan of 1,000 to 2,000 hours. This results in increased uptime, less maintenance, and fewer bulb replacements.

As single LED bulbs get older, the light will still function but emit less energy. To compensate for the lost power, the lamp can be turned up to a higher intensity instead of having to be replaced right away.

One of the first industries to use HG UV and later LED UV curing for inks and coatings was the printing sector. This was particularly true for flexo printers that used narrow web and sheetfed offset. A rising number of printers are upgrading production lines with existing UV curing systems to LED UV, since LED UV curing is becoming more and more common for digital inkjet and web offset presses.

Since LED curing technology has developed to provide faster curing, high-quality printing, and increased production output, it is the default curing method used by the majority of UV-curable inkjet printers available on the market.

Because LED UV can cure at lower temperatures, it is commonly used in flexographic presses to print on thinner films and a greater variety of label materials. The capacity to print on specialized substrates is the main reason why inkjet LED UV curing dominates the wide-format graphics business. Additionally, the majority of narrow web presses come with LED UV curing as standard equipment.

In industrial manufacturing, LED UV light has become the standard method for instantly curing UV-light-reactive adhesives, coatings, and finishes for improved bonding, sealing, coating, and finishing on a variety of substrates. Electronics, medical devices, plastic and automotive components, electric vehicle batteries, food and drink, wood furniture, construction materials, aviation and aerospace, venue safety and germicide, aluminum cans, and many more items are among its uses. Go here to learn more about industrial use cases.

Because LED UV lamps need specifically made solvent-free adhesives and inks, LED UV curing reduces the quantity of materials required and waste generated while also preventing the production of volatile organic compounds (VOCs), which lessens their impact on the environment.

The lamps do not produce ozone, a consequence of many print curing procedures that must be expelled from the work area, because LED UV emits UVA light. Mercury, a hazardous element found in arc UV lamps, is likewise absent from LED UV lamps, negating the need to handle and dispose of mercury arc bulbs in a safe manner.

Press rooms are safer when heat, ozone, and mercury are removed using LED-based UV. Additionally, LED UV improves the working environment by removing the ambient noise and stink caused by traditional systems, as well as the expenses involved with cooling air blowers and ozone extraction systems.

Finally, compared to arc mercury UV, LED uses a lot less energy.

uv light

Unlike drying solvent-based inks and adhesives, LED UV interacts with a photo initiator mix to provide a rapid cure, obviating the need for drying. After printing, printed items can be sent straight to post-production processes like binding and trimming.

In contrast to traditional arc-based lamps, which stay on during production and require an initial warm-up phase that delays production, LED-based UV lamp heads have the benefit of being able to power on and off rapidly, allowing them to be switched on and ready to cure right away.

When compared to a mercury arc UV system of the same size, LED curing systems use around 65% less energy. LEDs take a lot less electricity to operate than a UV bulb, which needs an electrical arc to generate enough heat to evaporate mercury and produce UV light.

LED UV's quick on/off procedure not only increases output speed and capacity but also significantly reduces energy consumption and bulb stress associated with traditional "always-on" UV mercury lamp curing. Additionally, because LED UV has no moving parts, it saves maintenance time on other components like fans, shutters, reflectors, and ballasts that are common in arc-based lamps.

In contrast to UV arc lights, which deteriorate over time, LED UV curing guarantees steady output, which provides an additional advantage. Better process and quality control result from the elimination of the requirement for ongoing monitoring and preventative bulb replacement.

Going one step further, operators may design the precise UV energy required for varying process requirements to minimize product loss, increase production capacity, and make the best use of production lines. In systems with several units, it is also feasible to switch off individual modules to conserve energy without lowering output or sacrificing quality.

Additionally, by doing away with the requirement for dryers in traditional ink presses, which not only directly use energy during the printing process but also raise cooling expenses in the printing facility, lower-heat curing lowers electricity consumption. When employing film substrates, the high heat levels produced by mercury arc UV lamps may necessitate the use of cool rollers. Although the heat is prevented from distorting the film by these cooled rollers, cooling the water requires an energy-intensive chiller system.

The lifespan of LED UV lamps is not shortened by frequent start-ups and shut-downs; instead, operators may benefit from the quick start-ups and shut-downs by turning off LED UV during downtime to prolong the lamps' lives.

Conventional UV and LED UV formulations share many of the same components. The photo initiator mixes are the primary area of difference. Unlike LEDs, which produce a single frequency and hence require a corresponding specialized photo initiator to carry out a curing process, conventional formulations comprise combinations that initiate curing over a wide range of mercury lamp frequencies. 385 nm is the most widely used wavelength for printing ink.

Indeed, utilizing LED UV, producers may fully cure both regularly formed and irregularly shaped 3D products by positioning lights with varying energy dispersions. The best LED lampheads for curing dimensional things include optics that increase the wavelength of UV light without causing a sharp decline in dosage or peak intensity.

LED UV lights are incredibly low maintenance. The air filters and emissions window are routinely cleaned. Press operators will be able to determine when to start increasing the power to compensate for end-of-life performance drop-off by routinely measuring the UV emission from LED dies.