PCBA (Printed Circuit Board Assembly) Conformal coating material and thickness?

[Nicco]

Hi, friends,

Did anyone know what standard or protocol has defined the conformal coating thickness and material for PCBA(PCB assembly) for Automotive application.

I knew that's depend on the PCBA's or products located in where, (ex. powertrain, chassis, body). especially environmental temperature, humidity...etc.

Best regards,
Nicco

[justncredible]

For automotive I am not sure.

I do think IPC610 does have a section on CC and potting. There are diffrent levels so if your not sure contact your supplier engineer and make sure you are using the right spec.

Maybe another can expand on it more since it has been a long time since I worked in electronics. And we only potted for auto apps.

[Umang Vidyarthi]

Originally Posted by Nicco

Hi, friends,

Did anyone know what standard or protocol has defined the conformal coating thickness and material for PCBA(PCB assembly) for Automotive application.

I knew that's depend on the PCBA's or products located in where, (ex. powertrain, chassis, body). especially environmental temperature, humidity...etc.

Best regards,
Nicco

IEC 61249-2-12 is applicable for PCBs/PWBs.

Also have a look here for more standards & guidelines. :

http://www.thetestlab.com/data/june99.pdf

Umang

[Nicco]

Originally Posted by Umang Vidyarthi

IEC 61249-2-12 is applicable for PCBs/PWBs.

Also have a look here for more standards & guidelines. :

http://www.thetestlab.com/data/june99.pdf

Umang

Hi, Umang and justncredible,

Thanks !

my question is PCB have been mounted components (passitive and active), and I used epoxy with spray coating in components surface to prevent any humidy and temperature damage. I dont' know have any standard or protocol has demand the thickness for automotive/vehicle application. Maybe IPC-A-610D has been defined, I need to check it.

Best regards,
Nicco

[e006823]

Thickness can range from .0005" to .005", depending on material. I don't believe IPC-610 will address thickness. You may want to look at IPC-HDBK-830, IPC-CC-830 (or Mil-I-46058)


Regards,

[w_grunfeld]

Nicco,
Probbably IPC-CC-8308:2002 is what you need.
However bear in mind that coating thickness is hard to control, especially when applied by spraying, and in any case coating thickness cannot be measured directly. All specs that I know, involve spraying special test specimens (flat glass) at the same time as the actual board and measuring the thickness on the glass specimen.
It is kind of b...t , since it all depends on the skill and steadiness of the operator's hand. Making a few samples that pass the test is no guarantee for production units.
Much more critical than thickness is coverage, and to achieve that make sure your coating material is UV fluorescent-means it is visible when inspected under a UV light.
I am guessing here, but I doubt there is a thickness requirement specific for automotive. I think in automotive you will have to pass humidity and salt spray test of the finished board to indirectly qualify the coating.