Just a thought here, but if the leads are sealed with a glass, bending the leads may break the fret seal and that's why they are concerned. I looked at the part, (but not in depth) to see if it was sealed and it said yes, so that may be why they want it potted. Shearing the leads may cause a shock to the lead and crack the seal? Bending the leads out to match the board pattern would do the same thing, so special fixturing may be needed to hold the leads near the part and bending farther away in addition to lead clipping? From a past company that did space work, leads that are sealed were not allowed to be bent, "sealed" leaded parts, were just soldered, etc. Hope this helps...
Scott Decker – Senior Analyst, Drafting & Design Services CID+ – Electronic Systems Center
UTC AEROSPACE SYSTEMS
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From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Thursday, July 28, 2016 8:12 AM
To: [log in to unmask]
Subject: [External] [TN] Prepping TO-5 can style Relay...
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:
So we have a Simonds CLP274 lead processor with a die that matches the footprint on the PCB:
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
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:
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.
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