The hottest factor affecting curing UV light sourc

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Factors affecting the curing UV light source

the performance of the cured UV lamp can be completely and accurately connected with four characteristics: UV spectral distribution, radiance, radiation amount and infrared radiation

1. spectral distribution

describes the wavelength distribution of phase radiation energy or radiation energy reaching the surface layer as one of the functions of lamp emission wavelength. It is often expressed in a related standardized term. In order to display the distribution of UV energy, the spectral energy can be combined into the spectral band of lonm to form a distribution table. This allows comparison between different UV lamps and makes it easier to calculate spectral energy and power

wavelength of ultraviolet ray the effective wavelength for ultraviolet curing is 200nm-400nm

generally, multi band ray detectors are used for detection to characterize the spectral radiance or radiation amount. The relative information useful for spectral distribution is obtained by sampling the radiation energy in a relatively narrow frequency band (20hm-60nm). Due to the different structures of ray detectors from different manufacturers, it is possible to compare them with each other, but it is very difficult. There is no such standard to compare models and manufacturers

spectral distribution data of UV tube metal halogen lamp and mercury lamp:

high pressure mercury lamp is in the range of 365nm as the main wavelength, 254nm, 303nm and 313nm. The high-efficiency ultraviolet wavelength is mainly used in the curing of UV light oil and ink; Metal halogen lamp mainly emits ultraviolet wavelength in the range of 200nm-245nm. Compared with high-pressure mercury lamp, long wavelength ultraviolet light emits more, which is mainly used in the curing of UV ink

2.uv radiance

radiance is the radiation power reaching the unit area of the surface. Radiance, expressed in watts or Howards per square centimeter. It varies with the output power and efficiency of the lamp, the focus of the reflection system and the distance to the surface (it is the characteristic of the lamp and its geometry, so it has nothing to do with the speed). The reference of high intensity and peak focusing power directly placed under UV lamp is peak radiance. Radiance includes all factors related to power supply power, efficiency, radiation output, reflectivity, focusing bulb size and geometry

due to the absorption characteristics of UV curable materials, the light energy reaching below the surface layer is less than that of the surface layer. The curing conditions in these areas may be significantly different. Materials with thick optical thickness (high absorption, thick physical structure, or both) may reduce light efficiency, resulting in insufficient curing in the deep layer of the material. The higher radiance of the surface in the ink or coating will provide relatively high light energy. The depth of curing is more affected by radiation than by longer exposure time (radiation). The influence of radiance is more important for films with high absorption (high opacity)

high irradiance allows the use of fewer light triggers. The increase of photon density increases the collision of photon light trigger, which compensates for the decrease of light trigger concentration. This is effective for thicker coatings, because the light trigger on the surface absorbs and prevents the light trigger molecules with the same wavelength from reaching the deep layer

3. UV radiation

the radiant energy reaching the unit area of the surface. The amount of radiation represents the total amount of photons reaching the surface (and the radiance is the rate of arrival), which is also relatively expensive. Under any given light source, the amount of radiation is inversely proportional to the speed and directly proportional to the amount of exposure. Radiation is the time accumulation of radiance, expressed in joules per square centimeter (there is no information about radiance or spectral content, which is only the accumulation of energy on the exposed surface). Its significance lies in that it is the only characteristic display that includes speed parameters and exposure time parameters. Recently

4. Infrared radiation density

infrared radiation is mainly the infrared energy emitted by the quartz bubble of UV source. Infrared energy and UV energy are collected together and focused on the working surface. This depends on the reflectance of IR and the efficiency of the reflector. LR energy can be converted into radiance or radiance units. But usually, the surface temperature it produces is the important thing to be noticed, and the heat it produces may be harmful or beneficial

there are many technologies that combine UV lamps to solve the relationship between temperature and IR, which can be divided into reducing emission, transferring and controlling heat movement. The emission reduction is achieved by using small-diameter bulbs, because it is the surface area of the hot quartz that emits several IR's. The reduction of transmission can be achieved by using a dichroic reflector behind the lamp, or by using a dichroic window between the lamp and the target. The heat movement reduces the temperature of the target, but only after IR has caused the temperature rise, the cold air flow or heat dissipation device can be used to control the heat movement. Absorption of IR energy, so when we require a thick cardboard, we can adjust the breakpoint ratio to about 60. However, we remind our customers not to adjust the breakpoint ratio too small, which will reduce the service life of the rubber film. The material itself determines the ink, coating or tomb piece. Velocity has a significant effect on the temperature caused by the incident IR energy and the energy absorbed by the working surface. The faster the process, the less m energy is absorbed, 4 Packaging and process function implementation machine (including packaging drop implementation machine, packaging impact implementation machine, friction and wear implementation machine, bending implementation machine, straightening machine, etc.); Cause the temperature to rise. The production process can be accelerated by improving efficiency

author (Wu Qun)

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