The optimal UV wavelength for a PCB UV curing machine generally falls within the UVA range, specifically between 365 nm to 405 nm. Among these, 365 nm is commonly used because it aligns well with the absorption peaks of many photoinitiators used in PCB coatings, triggering efficient curing. However, wavelengths like 385 nm, 395 nm, and 405 nm are also effective and in some situations may yield better curing results due to higher LED efficiency at these wavelengths.
Key points for PCB UV curing:
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Typical effective wavelengths are around 365 nm, 385 nm, 395 nm, and 405 nm.
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The choice depends on matching the LED wavelength to the absorption profile of the coating’s photoinitiator.
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Although 365 nm is a usual standard for PCB coatings, 395 nm or 405 nm might produce faster or more uniform curing under certain conditions due to better LED efficiency.
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UV curing for PCBs usually uses UV light in the range of 320-400 nm (UVA region) to activate the curing process in seconds.
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The intensity and exposure time also play important roles in achieving optimal curing without damaging components.
In summary, 365 nm is often considered the optimal wavelength standard for PCB UV curing machines, but systems operating at 385 nm to 405 nm are also widely used and can be better depending on the specific coating and LED efficiency characteristics.
Additional considerations:
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Proper UV intensity (100-300 mW/cm²) and exposure time (often 10-30 seconds) are critical along with wavelength.
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The lamp type, curing environment, and PCB component geometry also influence the effective curing performance.
This wavelength window ensures effective photoinitiation, deep curing penetration, and good adhesion for UV-curable PCB coatings.