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July 2016

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Subject:
From:
Steve Gregory <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Steve Gregory <[log in to unmask]>
Date:
Thu, 28 Jul 2016 09:12:17 -0600
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text/plain (57 lines)
Hi All,

We're building a board for a customer that uses a 8-lead TO-5 style relay.
The footprint on the board requires that the leads are spread out to a
larger diameter circle than what diameter is when they come out of the body
at the bottom of the relay. Here's the information for one of the relays,
there are three others that are the same style:

http://www.digikey.com/product-search/en?lang=en&site=us&WT.z_cid=ref_findchips_standard&mpart=PRMAC-26X

So we have a Simonds CLP274 lead processor with a die that matches the
footprint on the PCB:

http://stevezeva.homestead.com/Simonds_CLP274.jpg

We insert the part which spreads the leads out, then step on the pedal and
a guillotine style blade shears the leads off. I've used the prep unit
many, many time before at previous employers without issues. The customer
is saying that prepping the leads in this unit is damaging the relay. So
now we are to pot the leads before prepping them with a 2-part epoxy using
a tooling fixture as a mold for the epoxy, and the potted relay looks like
this:

http://stevezeva.homestead.com/Potted_Relay.jpg

Has anybody ever heard of this Simonds unit damaging relays like this? Has
anybody had to add potting to a relay like this? I can understand wanting
to keep the leads coming straight out of the bottom of the body before
making the bend to match the footprint on the board, but I think I can use
a Bivar permanent spacer and slip it over the lead and accomplish the same
thing. Something like this:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwiqk8zCt5bOAhWJ1IMKHebaCR8QFggxMAE&url=http%3A%2F%2Fwww.bivar.com%2Fportals%2F0%2Fproducts%2F616-070.pdf&usg=AFQjCNESVvvX6qOo_-0T94sAYNLP8AJ21Q&cad=rja

Or even a nylon washer that matches the diameter of the lead pattern
(.200") coming out of the bottom of the relay. Potting this relay is going
to be very time consuming and there's going to be a risk of getting the
epoxy on the leads that will ruin the solderability of the part. I'm just
trying to understand if it is truly the Simonds prep unit causing the
damage, and if this really is, and easier way other than potting them to
accomplish the same thing.

Thanks all!

Steve Gregory

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