What's the Difference between LED UV Curing and Mercury UV Curing?

UV curing is a minimal temperature, quick, solvent-free photochemical process that transforms inks, adhesives, coatings, or other photo-reactive materials into solids that are instantaneously fixed in place using polymerization under high-intensity UV light. UV curing devices use a range of lamps as UV light sources, including LEDs that output UVA radiation, and mercury-based arc lamps, which produce broad-spectrum Ultraviolet light. At IUV, we provide professional curing services fit for both commercial and industrial use.

These two curing options might be familiar to those in the wide digital format printing industry. The development of Mercury curing and UV LED curing techniques is among some of the rapidly expanding fields in printing and UV coatings. Both techniques have their share of benefits and shortcomings that we will discuss today.

What is LED UV Curing?

High-intensity electrical UV light is used in LED UV curing to transform inks, adhesives, and other photo-reactive materials into immediately set-in-place solids via polymerization. In contrast, "drying" concentrates chemicals by absorption or evaporation.

Its benefits are vast and quantifiable to many production and printing companies, ranging from a cooler, cleaner cure than that accomplished with mercury arc bulbs. LED UV curing hosts all the benefits of conventional UV curing with the addition of solving issues that accompany heat-set drying. They include instant turn-on/off, uniform and quick dry curing, minimal heat output, and minimal power consumption. Furthermore, LED UV's compact form nature makes it the best choice for integration into procedures or equipment with limited space.

Major Benefits of LED UV Curing

The major benefits of LEDs originate from the diode aspect of light emission. LED has advanced over the years; even old TV sets that used cathode ray tubes have been swapped for HD LED TVs. Even incandescent bulbs have been swapped for better-performing LED lights.

Quartz tubes require some mercury to produce UV lights for curing and can be replaced by LED UV curing systems. Mercury UV curing systems consume high energy levels and generate much heat compared to LED UV curing systems like this.

Mercury lamps, specifically the famous arc lamp, degrade each time it's switched on or off. It requires expert engineering and management to manufacture and maintain mercury arc lamps that produce uniform output. On the other hand, LEDs are extremely reliable and output consistent light over long periods. They consume less power, have longer wavelengths, and produce less heat.

What is Mercury UV Curing?

The powerhouses of the curing business are mercury curing lamps. They have a life expectancy of 1,500 hours and produce IR and UV light in the 350–380 and nm 240–270 nm sections of the spectrum. They produce heat and consume a lot of energy. This has the disadvantage of damaging delicate substrates while hastening the crosslinking of polymeric materials, making it unsuitable for printing thin materials.

Even if the printing machine is not in use, these lamps must be kept on because they take a significant period to heat up and cool down. This increases the energy expense.

Major Benefits of Mercury UV Curing?

Mercury uv curing still rules the market amidst these disadvantages as it is highly productive. The wide range of spectral dispersion of mercury lamps and their capacity to change the output's spectral region to various UV spectrum regions is one major benefit in contrast to LED systems.

As a result, a variety of photo-initiators with different action spectra can be used (and blended) to react to short or long wavelengths, influencing deep cure by different wavelengths and upper cure by short wavelengths. Until LEDs can equal their performance, particularly their efficiency and depth of cure, the technique will continue to rule the broad format digital print market. The turning point won't occur for some time, but it might happen sooner than anticipated.

Conclusion

The main difference between the two is that mercury curing emits light over a very wide wavelength region, allowing industries to fully capitalize on the reactivity of the system's components and therefore maximizing faster speeds in productivity.

In contrast, LEDs emit light in a much narrower wavelength region, which limits the reactivity rate. Of course, LEDs still have many advantages over Mercury, as stated above, and they are more environmentally friendly.

Therefore, LEDs can be a good solution depending on the type of application. LED might surpass mercury lamps as more advances in its field are made in the future. However, right now, LEDs are suited for lower productivity equipment.