TPT March 2024

ARTICLE

Allied UV

2. Microwave light curing technology

Outlined below is a brief graphical summary of advantages and disadvantages of UV cure technology:

Figure 4: Heraeus F600 – 600W – lamp

Figure 6: Colour chart – UV cure technology summary – colour charted with colour key

Microwave lamp summary • Typical bulb life – 6,000 to 8,000 hours • Continuous power output/minimal degradation of power (UV energy output) over time • 9KW energy usage/hour per lamp – large energy consumer • Different curing wavelengths • Broad band emission 200 to 450nm • Bulbs contain mercury Instant on/off • Heavy components – 180lb power supply and 40lb lamp head • Very large physical footprint • Magnetrons may retain a high voltage charge after power has been disconnected, proper training is required to safely work on the UV lamp system • It is not recommended that the lamps shine into each other – this can increase the length of the curing system • Costly and noisy air handling system – large ductwork with significant cost • Medium maintenance (regular replacement of consumables • Large capital investment overall

When you pair LED light curing technology with LED formulated UV coatings, the combination offers the best energy savings solution along with the best coating sustainability solution. Outlined below are the advantages associated with LED cured UV coatings technology: • UV coating – NO VOCs or HAPs – sustainable solution • Instantly dry • No post ovens (water-based coatings) • Typically, lower cost per linear foot than water-based coatings

• Still no temperature or humidity issues • No freeze/transportation/storage issues • All colours/effects coatings available • Clear, tinted, colour, metallic options etc • Better overall coating/curing technology

It is critical to ensure that your UV coatings are developed for the specific wavelength associated with your LED curing light output. Currently available wavelengths are 365, 385, 395 and 405nm as outlined in the associated table below:

3. LED light curing technology

Figure 5: LED lamp head

LED lamp head summary • Typical LED life – 50,000 hours • Higher power offerings upcoming • Minimal degradation of power (UV energy output) over time • Continued advancement in LED efficiency (UV energy output vs electrical power) power output/Watts • 2.5KW energy usage/hour per lamp • Narrow band UV emission 365, 385, 395 or 405nm • No mercury bulbs • Ozone free • Much lighter weight • Significant reduction in noise • LED is either air or water cooled integrated cooling blower • Significant energy savings compared to mercury lamps • Low maintenance (no consumables) • No ducting/elimination of large capital cost • Very small footprint – typical system less than 10ft line space

Figure 7: Wavelength vs irradiance for conventional mercury lamps and UV LED systems

In order to achieve all the benefits of a LED-cured UV coating solution, the technologies must be paired together to ensure proper coating performance and curing results. The user should not take a standard mercury microwave or arc lamp coating and “experiment” with LED curing technology – this would be a costly and time-consuming mistake. Also, make sure the coating supplier is an expert in both UV LED coatings and UV LED curing technologies and not your typical water-based/solvent-based coating supplier, who just dabbles in UV.

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MARCH 2024