EEVblog Electronics Community Forum
Electronics => Projects, Designs, and Technical Stuff => Topic started by: walkeryyj on May 24, 2018, 09:38:48 pm
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Hi all,
I have a project where we have a small fairly complex PCB with lots of SMD components (as small as 0402). The device will be subject to strong vibration and needs to be potted for other structural/mechanical reasons (it’s part of a motor and load transfer is something we need to take into account.)
I have selected an epoxy that seems to be a good fit with respects to thermal conductivity and hardness (D90, Tensile Strength ~10,000 PSI) etc however what I am concerned about is having components tear off our boards while being thermal cycled.
The material I’m looking at is marketed as having low shrinkage (.002 In/In) and lists its thermal expansion at 1.5x10^-5 in/in F. The PCB measures maybe 1.2”x6” and will live in an epoxy block that is ~ 2”x2”x 7”. Normal operation will be 25C to 80C but COULD be used in an environment as low as -30 C
Can anyone give any insight into if we need to be concerned about PCB failure due to the epoxy destroying components?
What’s best practice here?
Thanks!