UV Curing Equipment Information
UV curing systems use ultraviolet radiation to initiate reactions and cure adhesives, coatings, stereolithography polymer resins and other UV curable resin products. To provide ultraviolet illumination, UV curing systems use a flood, spot, or focused beam of light. Flood lamps provide a broad or wide beam of UV light. Focused, wand and spot systems provide a collimated or narrow beam of UV light. The power of UV curing systems is specified by lamp intensity (watts) and/or illumination energy (watts or power per unit area). Some UV curing systems include an integral timing unit or hour meter to control exposure time. Other systems include filters for specific applications, side or multiple direction curing, and LED light sources. Computer interfaces for programming, control, or data acquisition are also available.
UV curing systems are available in a variety of configurations. Curing chambers consist of a power supply, UV light source and enclosure or chamber that provides a work surface and shields the operator from UV radiation. UV conveyors or continuous systems typically consist of a belt conveying unit, power supply and UV light source, as well as an enclosure that is open on both ends, which allows products or sheets to pass through the system. Handheld or portable UV devices are useful for repair, testing and other applications in field, laboratory, plant floor, and other settings where transportation of large systems is impractical. Stand-alone UV curing systems may have a chamber conveyor enclosure, or a work surface with or without a UV-absorbing curtain or shield. Flood or focused UV sources or modules are also integrated in production lines. Process or line mounted UV systems include a power supply, light source and flange, cartridge mounting or fitting, web system, coating line, and conveyor lines or tanks that transport chemicals, plastic film, or other transparent media for processing. Spot or wand systems are benchtop units that provide a UV beam with a small spot size for selective curing applications. Flexible wands or lights can be positioned to cure specific regions on an assembly. Some UV systems can feed multiple wands or light pipes.
Most UV curing systems produce ultraviolet radiation falling into one to three UV bands: UVA, UVB and UVC. UVA is the near or long wave UV band (~315 - 400 nm). Also known as black light, UVA makes certain pigments fluoresce. UVA has little effect on pathogens and no effect on human tissue. UVB is the middle UV band (~280 - 315 nm). Also know as the suntan ultraviolet band, UVB is used in tanning salons and in some industrial applications. UVB inactivates a moderate amount of pathogens, but is not as effective as UVC in destroying bacteria. Prolonged exposure to UVB results in blistering of the skin and cornea damage. UVC is the germicidal or short wave UV band (~200 - 280 nm). When used correctly, UVC or ultraviolet germicidal irradiation (UVGI) inactivates pathogens by destroying their DNA and RNA, rendering the microbes impotent. The ideal wavelength for eradicating pathogens is 253.7 nm. Prolonged exposure to UVC causes a temporary reddening of the skin and a temporary eye irritation commonly known as welder's eye. No known permanent damage is caused by extended exposure.
Some UV curing systems also produce visible or UV-visible light such as light in blue green region (~395 - 455 nm). Visible light capability is useful for adhesives with dual UV / visible cure capability. Other less common or specialty UV frequency bands include the VUV or vacuum UV band (100 to 200 nm).