What is UV Curing and How Does it Work?

Ultraviolet curing (UV curing) is a method of irradiating ultraviolet rays (UV) into ultraviolet curing resin (UV curing resin) in order to cure the resin in a short time. Its use of ultraviolet light is where it gets its name.

But how does it really work?

UV curable resin is composed of monomers, oligomers, photopolymerization initiators, and other additives.

When exposed to ultraviolet light (UV light), the photoinitiator undergoes a chemical reaction that allows it to bond independent oligomers and monomers into a more complex chain. These chains are called polymers. This bonding process, called a “photopolymerization reaction”, is what takes a resin from its liquid state to a solid state. Via this photopolymerization reaction, you can dry, bond and paint objects and materials by curing. This is why UV curing is also called UV drying, UV bonding, UV coating, etc. 

So what is UV light? It is a light ray with a wavelength of 100 to 400 nm. The shorter the wavelength, the higher the energy and the destructive power to the living body. It is further classified into A, B, and C depending on the wavelength length.

  • UV-A: Long wavelength UV 320-400nm

  • UV-B: Medium wavelength ultraviolet ray 280-320nm

  • UV-C: Short wavelength UV 100-280nm

The UV LED irradiators we carry from Micro Square Co., Ltd. perform in the UV-A to UV-B ranges.

Interested in learning more of the science and scientific considerations that come into play with UV curing? Visit our page on Wavelengths and Photoinitiators, as well as our breakdown on what exactly Total (Integrated) Light Intensity is and why it matters in curing.

What are Common Applications of UV Lights and UV Curing?

Most applications of UV curing fall into 3 categories:

  1. Drying Examples - Printing (drying ink, drying DVD label), printing electronic components

  2. Adhesion Examples - Adhesion of optical parts, adhesion of precision electronic parts, adhesion of medical equipment (injection needle)

  3. Painting Examples - Coating and drying molded products, furniture, and floor materials

But beyond just curing, UV lights are also used in research and manufacturing as an inspection tool. Fluorescent penetrant inspection (FPI) is the process of applying a fluorescent dye to a surface and then viewing under UV light in order to detect material and production flaws. How cool is that?

Here’s a list of real-world products that often use UV technologies.

Example Applications

  • UV-hardened gaskets on waterproof camera ( and cellphone) parts

  • UV curing adhesion of camera lens

  • UV adhesive curing of electronic substrates

  • UV bonding of smartphones components

  • Waterproof UV silicone curing for tablet PC cases

  • Curing UV urethane applied to cars

  • Curing UV epoxy paint for woodwork

  • UV curing of cable protection film

  • UV curing for surface protection of concrete

  • Laminating UV curing for OLED manufacturing

  • UV for photocatalyst

  • UV for fluorescent flaw detection

UV Technology in Manufacturing Takeaways

What should we take away from this information?

With there being hundreds of unique applications for UV curing and general UV technologies, you can imagine there are thousands of different UV light configurations to meet different needs. There is no one-fits all solution.

This is why we’re so proud to represent Micro Square. With over 500 configurable designs, we’re prepared to fit your needs regardless of whether you’re looking for a single handheld device, or a solution for large-scale productions line.

Ready to Learn More?

Check out our guide on how to choose the right UV LED System, view our products, or contact us with your questions.