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

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Conformal coating

Sam

#26982

Conformal coating | 26 January, 2004

Does anyone know, what causes the orange peel affect when spraying pcbs with conformal coating ? Are there ways of minimising or eliminating this ? Is is possible to achieve a glass like finish ? if so how

Thanks

Sam

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#26994

Conformal coating | 26 January, 2004

You should be able to obtain a smooth finish. A "glass-like finish" is in part a function of the coating material, assuming good process.

When we see "orange peel" conformal coating, we think moisture from the spray room environment, conpressor, etc. There are other, secondary, causes: * Spraying at high viscosity�s [Ensure proper thinning] * Air pressure too high [Reduce air pressure] * Poor spray technique, such as spraying too far from surface [Move closer to surface]

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blnorman

#27054

Conformal coating | 29 January, 2004

What conformal coating are you using - silicone, acrylic, urethane?

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Sam

#27077

Conformal coating | 2 February, 2004

The Type we predominntely use is Acrylic, but we also get this problem when we use silicone or urethane.

Sam.

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Vadim

#27183

Conformal coating | 10 February, 2004

At times the orange peel effect can be from excess flux improperly removed. Our company strictly provides the service of selctive conformal coating application. We quite often see this. Most times if the board is simply "water washed", or IPA washed, this will end the problem. Sometimes the thickness of the coating can be increased if washing is not an option, or apply the coating at a slower speed.

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Maryann

#27184

Conformal coating | 10 February, 2004

At times the orange peel effect can be from excess flux improperly removed. Our company strictly provides the service of selctive conformal coating application. We quite often see this. Most times if the board is simply "water washed", or IPA washed, this will end the problem. Sometimes the thickness of the coating can be increased if washing is not an option, or apply the coating at a slower speed.

Maryann

reply »

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