The UV curing process revolves around moderate temperature, slightly elevated speed, and a solvent-free photochemical technique that employs super-intense electrified UVs. As a result, the process polymerizes inks, varnishes, resins, and photo-reactive compounds through a promptly positioned solid.
Unlike "drying," which solidifies chemicals by evaporating or absorbing, UV curing should result in cured items that are securely bonded to the substrates where they are placed. Further, this brings out sufficient cure depths that are neither tacky, sticky, nor flaky.
UV curing techniques comprise spot and flood. On the other hand, there are options such as hand-held and conveyor curlers. Some curing devices may employ a range of ultraviolet mercury-based lighting emitters. Also, these sources guarantee broad-spectrum UVs and LEDs. However, they only emit UVA radiation.
UVC LEDs are still viable options, but their energy production and efficiencies are significantly lower. So, HG, or arc lighting, has been the standard in UV curing and printing for quite a while. Despite this, they generate a lot of heat and consume a lot of energy. Again, they destroy the ozone and require lots of exhaust. On the other hand, their disposals follow tight regulated scrutiny.
How does UV curing work?
The UV curing process converts the materials into a solid, durable material used to make parts or products. The light in this process has a wavelength much shorter than visible light but longer than infrared light.
UV light interacts with the pigments in your resin, causing them to react with each other and form microscopic crystals within the resin. This crystallization process occurs very slowly, so it takes several hours for everything to dry out and harden into a hard solid material.
How does UV curing differ from other processes?
UV curing differs from other processes because it produces a hard, crystal clear, and crisp surface. This process can be used on various plastics, wood, paper, and glass.
UV curing is an in-line treatment that uses ultraviolet light to cure the resin in a small conveyor system. The resin is mixed with pigments and additives; then, it is poured into molds or castings to create the finished product.
The advantages of LED UV curing
Quick reaction
The resin cures very quickly, so there is no need for extra time or waiting for the material to dry before moving on to the next step. It also creates an excellent quality resin because it cures at room temperature with no problems with shrinkage or warping, as other methods may have caused.
The equipment used for UV curing can be easily moved, so it doesn't take up much space when drying out before packaging or storing items that require special packaging’s, such as pharmaceuticals or food products.
Eco-friendly
LED UV lamps necessitate specially engineered solvent-free polymers and inks. Thus, it prevents the production of volatile chemicals. Also, LED UVs release UVA radiation, not ozone gases, as do other print curing methods. They contain no mercury, so you never have to worry about bulb disposal.
Efficient and power saving
Unlike traditional arc-based bulbs, which are slow and require pre-heating, LED UV curing systems only turn on when needed. As such, LED UV cures and the rapid on/off procedure of LED UV significantly reduce energy consumption and stress on the bulb. Again, movable parts are absent. As a result, they cut off unnecessary repairs.
Typically, LED UV bulbs last up to 19,999 hours. That's longer than arc-curing bulbs, which last 999 to 1,999 hours. As a result, there is increased uptime, fewer service calls, and bulb changes. Furthermore, less-heat curing minimizes energy usage by removing the requirement for a dryer in the typical ink press.
Take away
As LED ultraviolet curing becomes more common in digital inkjets and flexography, many printers are upgrading their old UV curing devices to LED ultraviolet. Currently, ultraviolet ink jet machines employ LED curing as their standard curing process. It has progressed to ensure quicker curing, better printing, and increased output.
Following the introduction of a compact carriage to quickly drive a lightweight bulb throughout the breadth of the printers to dry the pigments, LED ultraviolet has continued to be the dominant UV printing technology for broad-format graphic and tag printing. HG arc lights' higher weight, larger surface, and cooling systems prevented this from being accomplished.
The capacity of LED UVs to cure at moderate temperatures is widely recognized as a game-changing innovation, with flexographic presses that enable writing on thin sheets and a larger variety of label materials. Since it can print on specialty substrates, inkjet LED ultraviolet dominates the marketplace for broad-format graphics.
