Any conco guru's out there,
you could stop blood being shed by providing an opinion on the following.
1       We have an assembly which has a small (2 1nch square) daughter board fitted very close to the motherboard (1/4 inch) in a face to face arrangement. Opinions are many and varied on how we conformally coat this arrangement. Results from the subbie have shown that conco'ing the complete assembly results in poor coverage of the mother top and daughter bottom side. What therefore is the best deal with this i.e. mask the assembly holes for the daughter board, conco the mother, seperately conco the bottom of the daughter, assemble mother to daughter, ......do we then clean these connections??, spot conco them afterwards?? is this acceptable??, why didn't i go to med/law school and have an easy life??
Conformal coating is an acrylic HPA200 by Electrolube

2       An associated question: the daughter board is to have a screening can over it. The can is to be soldered 100% along the bottom, which mates with a trace on the outside of  the PCB. The inner surface of the PCB is also to be conco'ed. What effect will the heat from the soldering operation on the can have on the conco??

As always any donation no matter how small is always appreciated


Regards
Ian Squires
Senior Production Engineer
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Graseby Dynamics Ltd
A Smiths Industries Company
Park Avenue, Bushey, Watford, Herts, WD2 2BW
Web Site: www.gradyn.co.uk
Phone:    01923-228566 xt 295
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