What to Measure?





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Irradiance is the radiant power arriving at a surface per unit area. With UV curing, the surface is most often the substrate and a square centimeter is the unit area. Irradiance is expressed in units of watts or milliwatts per square centimeter (W/cm² or mW/cm² ). In UV curing, the term ‘intensity' has commonly been used to describe irradiance. Irradiance more correctly describes the concept of UV arriving at the cure surface and is the preferred term.

UV irradiance is important in your process because it provides the ‘punch' to:

It is important to determine the minimum irradiance value needed for your process. Staying above the minimum will allow you to get the adhesion and penetration through your coating. Longer wavelengths (UVV) have better chance at penetration than the shorter wavelengths (UVC). More information about UV Basics. Often times the UV system with the higher irradiance will allow you to run at faster belt speeds. Higher irradiance values may also increase cure rate efficiencies.

A radiometer can report the highest irradiance measured (peak irradiance) and/or profile of the irradiance over time (irradiance profile).

In processes where multiple UV lamp systems are used, a profile of the irradiance over time will allow the user to confirm that each lamp system is performing as designed. Measuring Multiple Lamps

Lamp Design Factors Affecting Irradiance

Lamp Configuration and Maintenance Factors Affecting Irradiance