Yes, absolutely. I had totally forgotten about the glass seals. Good point, Dr. Creswick!
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steven Creswick
Sent: Thursday, July 28, 2016 11:24 AM
To: [log in to unmask]
Subject: Re: [TN] Prepping TO-5 can style Relay...
Now then, coming from a microelectronics perspective, I still look at things from a hermeticity point of view.
If the leads have individual glass to metal seals, or if the entire back-side is glass-filled, one could easily disrupt the glass to metal seal at the glass/metal interface around the leads and result in loss of hermeticity.. This will show up as fine leak failures, and depending upon the use environment and time interval, could possibly result in a functional failure - but come on! Let's get real here.
I remain skeptical that their use environment is aggressive enough for long-term loss of hermeticity to become an urgent issue. More than likely, there was at some time a mechanical failure within the relay, (and as Phil said - knee jerk reaction). Details please!
If you don't observe visible evidence of glass fracture and lead pull-out (at a minimum of 30-50X), I suggest that you are okay.
But, to mitigate the potential problem, I would avoid splaying the leads out like that in the first place .... You are just trying to live with a potentially bad situation.
On Thu, Jul 28, 2016 at 11:55 AM, Nutting, Phil <[log in to unmask]>
> Sounds like a knee jerk reaction because there are failures and it is
> the one thing they see as different.
> We are engineers... the proof is in the data.
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
> Sent: Thursday, July 28, 2016 11:49 AM
> To: [log in to unmask]
> Subject: Re: [TN] Prepping TO-5 can style Relay...
> Hi Bev,
> To be honest, I don't know for sure, I'm assuming they do. I'm just
> trying to learn if anybody else has experienced this problem to see
> how widespread this might be...
> On Thu, Jul 28, 2016 at 9:44 AM, Bev Christian
> <[log in to unmask]
> > Steve,
> > Do they have PROOF that bending the leads cause damage?
> > Bev
> > -----Original Message-----
> > From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
> > Sent: Thursday, July 28, 2016 11:12 AM
> > To: [log in to unmask]
> > Subject: [TN] Prepping TO-5 can style Relay...
> > Hi All,
> > We're building a board for a customer that uses a 8-lead TO-5 style
> > 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=re
> > f_
> > findch
> > ips_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=
> > 0a
> > hUKEwi
> > qk8zCt5bOAhWJ1IMKHebaCR8QFggxMAE&url=http%3A%2F%2Fwww.bivar.com%2Fpo
> > rt
> > als%2F
> > 0%2Fproducts%2F616-070.pdf&usg=AFQjCNESVvvX6qOo_-0T94sAYNLP8AJ21Q&ca
> > d=
> > 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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