We are having problems with relay package seals cracking and moisture intrusion in power relays on thru-hole assemblies. we use a few different brands of thru-hole relays, we are using a sn-pb process right now and just going to lead-free. the contract manufacturer says that their process is very consistant, and meets the manufacturers process specs.
we dont want to have to hand solder these parts but we are very worried about future field failures.
You're correct: * Sealed relays should not be cracked or have moisture intrusion. * Hand soldering relays is going to be expensive. [Using a mini-solder pot for this might reduce some of the burden.]
The good part is that the problem is gross enough that you're taking-on water and is not something that is less obvious. It's coming from some where and wave soldering of the board is the first place we'd look to find it. So go to your contactor to: * Review the documentation on process control * Check the relays in the stock area for cracking and moisture * Wash some relays * Check the relays for cracking and moisture * Wave the assembled boards with your clean relays * Check the relays for cracking and moisture * ... and on and on
... all the while, making it seem like your contractor came-up with the plan to find the cause of the cracking, of course.