PCB UV Curing for Conformal Coating Solution

I. Function of UV LED wavelength bands

1.UVA wavelength band (320 - 400nm): It is the main wavelength band for curing PCB three-proofing paint. Specific wavelengths such as 365nm and 395nm can cause photoinitiators in the three-proofing paint to generate free radicals, triggering polymerization reactions and allowing the three-proofing paint to cure into a protective film. It has moderate penetration to the PCB surface and does not damage electronic components.

2.UVB wavelength band (280 - 320nm) (optional): Some special three-proofing paint formulations use its energy to assist in accelerating curing, especially when the paint layer is thick or rapid curing is required. However, the intensity and time must be strictly controlled to avoid damaging the PCB and components.

II. Solution principle

1.Photoinitiator activation: UVLED ultraviolet irradiation causes the photoinitiator in the three-proofing paint to absorb photon energy, transition from the ground state to the excited state, and the chemical bond breaks to form active free radicals or ions.

2.Curing by polymerization reaction: Active species react with monomers and oligomers in the three-proofing paint. For example, in free radical polymerization, the paint layer is cured to form a paint layer with good protective performance. It cures quickly and is environmentally friendly without affecting the performance of the PCB.

III. Customization process

1.Analyze PCB and three-proofing paint: Understand the type, material of the PCB and the formulation of the three-proofing paint. Different situations have different requirements for the UVLED curing system.

2.Determine the wavelength band and power: Select the appropriate UVLED wavelength band and power based on the analysis. If the UVB wavelength band is required, be cautious and determine the best combination through experiments.

3.Design the structure of the curing system: Determine the number, arrangement of UVLED beads and the distance from the PCB to ensure uniform illumination and avoid damaging the PCB.

4.Optimize and test parameters: Optimize and test the curing parameters before production. Test with sample PCBs, detect the performance of the three-proofing paint and the condition of the PCB, and adjust to the best.