About UV lamp performance

The effects of curing UV lamps can be fully accurately linked with four characteristics: UV spectral distribution, irradiance, amount of radiation, and infrared radiation.

1, spectral distribution

Describes the wavelength distribution of the phase radiant energy or radiant energy that reaches the surface layer as one of the functions of the lamp's emission wavelength. It is often expressed in a related standardized terminology. To show the distribution of UV energy, the spectral energy can be combined into 10 nm spectral bands to form a distribution table. This allows comparison between different UV lamps and easier calculation of spectral energy and power.

Ultraviolet wavelength is effective for UV curing from 200nm to 400nm

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

UV Lamps Metal Halide and Mercury Lamps Spectral Distribution Data:

The high-pressure mercury lamp is based on 365nm as the main wavelength, near the 254nm, 303nm, and 313nm wavelengths. The high-efficiency UV-emitting wavelength is mainly applied to the curing of UV-light and inks; the metal halide lamp emits ultraviolet rays mainly in the range of 200nm to 245nm. Wavelength, compared with high-pressure mercury lamps, the release of long-wavelength UV light is mainly applied to the curing of UV inks.

2, UV radiation

Radiance is the radiated power that reaches the unit area of ​​the surface. The degree of radioactivity is expressed in watts per square centimeter or watts. It varies with lamp output power, efficiency, focusing of the reflective system, and distance to the surface (it is a characteristic of the lamp tube and geometry, so it is independent of speed). The high-intensity, peak-focus power reference placed directly under the UV lamp is the peak irradiance. Radiosity includes all factors related to power supply, efficiency, radiation output, reflectivity, size of the focused bulb, and geometry.

Due to the UV-curable material's absorption characteristics, less energy is reached below the surface than in the surface layer. 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 solidification of the material. Higher surface irradiance in the ink or coating provides relatively higher light energy. The depth of solidification is more affected by the irradiance than due to the longer exposure time (radiation amount). The influence of radioactivity is more important for highly absorbent (high opacity) films.

High radiation allows the use of less light triggers. The increase in the photon density increases the collision of the photon phototrigger, thereby compensating for the decrease in photo-trigger concentration. This works for thicker coatings because the photo-trigger in the skin absorbs and blocks the same wavelength from reaching deeper photo-trigger molecules.

3, the amount of UV radiation

Radiation energy reaching the unit area of ​​the surface. The amount of radiation represents the total amount of photons that reach the surface (and the rate of radiation is the rate of arrival). Under any given source, the amount of radiation is inversely proportional to speed and is proportional to the amount of exposure. The amount of radiation is the cumulative time of radiation, expressed in joules per square centimeter (no information about the radiometric or spectral content is replaced with information measured in terms of the amount of radiation, which is simply the accumulation of energy at the exposed surface). The significance of this is that it is the only characteristic manifestation that includes speed parameters and exposure time parameters.

4, infrared radiation density

Infrared radiation is mainly infrared energy emitted by a quartz bubble of a UV source. Infrared energy and UV energy are collected together and focused on the work surface. This depends on the IR reflectivity and reflector efficiency. The lR energy can be converted to radiation or radiometric units. But usually, the surface temperature it produces is important for attention, and the heat generated may be harmful and may be beneficial.

There are many technologies that combine UV lamps to solve the relationship between temperature and IR, and can be divided into reducing emission, transmitting, and controlling heat movement. The reduction in emission is achieved by using small diameter bulbs because it is the surface area of ​​hotquanz that emits almost all of the IR. The reduction in transfer can be achieved by using a dichroic reflector behind the lamp or using a dichroic window between the lamp and the target. Heat movement reduces the target's temperature, but only after IR has caused a temperature increase, cold air flow or heat sinks can be used to control heat movement. The absorption of IR energy is determined by the material itself, ink, coating or substrate. The speed has a significant effect on the temperature caused by the incident IR energy and the energy absorbed by the work surface. The faster the process, the less IR energy is absorbed, causing the temperature to rise. It can speed up the production process by improving efficiency.

Source: China Ink Technology Network