Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Acrylic comformal coat on PCB

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#68781

Acrylic comformal coat on PCB | 2 May, 2013

we have a Specialty coating system (SCS) precisoncoat spray coating system. we are using an acrylic coating material with about 80cp viscosity. The spraying pressure is around 4-6 psi. The main issue is the finish looking of the board. If we apply high spraying pressure, the coating surface on the board would be roughness (not uniform or smooth). This may be caused by the high spraying pressure. if we drop down the pressure and increase the coating flowrate, the coating thickness on the board is too large to qualify the IPC standard, but the coating surface is very smooth. Do you have any tips or idea to get a proper thin layer with uniform looking? I am appreciated.

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Lou

#68784

Acrylic comformal coat on PCB | 2 May, 2013

I would suggest lowering the viscosity even more. Humiseal even sells 1B31 pre-mixed specifically for spray machines and the highest they go is 65cps.

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#68785

Acrylic comformal coat on PCB | 2 May, 2013

Thanks for the advise, but we want to change the lacquer/thinner ratio at the last step if we don't have other solution.

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