Hermetic connectors

Yeah lots of hits... mostly I just see hermetic connectors, which are all expensive.

For one use I won't even have milli-torr vacuum, just reduced pressure (say a 1-100 torr.)..

I think I've seen the BNC's with O-ring for ~$50. Which is OK, but only one connection.

George H.

Thanks I did see a bunch of "water proof" connectors as listed as an option on digikey.

Thanks Matt, making cable /connector assemblies is a real PITA. One thing I like about the pcb idea is that I can make attaching the wires easier.

George H.

I don't think it[s catastrophic rupture that's going to be the problem with thin FR4, but rather reliability. That's where a nice thick piece of fibreglass is a win. If it's too thin thin, it'll still hold together OK, but you'll get stress concentrations at the edges of the holes, which may crack and leak.

For a 2-inch flange, I'd be thinking about 3-mm FR4 with filled vias, with the solder mask relieved top and bottom around the vias so that you can apply solder to make double-sure of no leaks. A SMT connector top and bottom will give you as many connections as you're likely to need, in an easily-replaceable form.

Cheers

Phil Hobbs

Yeah those would work too. We already use a bunch of these Hirose connectors, so that becomes my first choice.

Grin, I was laying pieces over a 1" diameter hole yesterday, and pressing with my thumb. With the connector solder on there it will be even stiffer.

George H.

Yeah well this is not for a "one of", it has to look nice too.

George H.

pcb with nine pads, wirewrap dsub from the outside, solder cup dsub on the inside?

-Lasse

Oh surface mount connector on the top side too... Hmm, you know one thing I worry about is electro-static pickup. For most of the lines that won't matter. But at some point I'll have high impedance signals on the connector. I'd like to keep everything "under ground" so to speak.

Did you see my pic of the Hirose 8 pin circular connector with the shell soldered to the pcb. That should be fairly stress free. At least that's how i'm going to start. (When faced with too many options, just try something. :^)

Hey thanks all for the advise and comments. Now all I have to do is get Hirose to give me a drawing of their connector. (Or just tell me the diameter of the bolt circle.) Their web site is a pain, and after I registered and waited a day for the confirmation.. I got an error message when downloading to drawing.

George H.

I'm a huge fan of repurposing HDMI cables for this sort of job. You can run the traces underneath the (grounded) connector shells, which will pretty well get rid of electrostatic worries.

The only drawback with HDMI is that the cheaper cables tend to be stiff, so you'll need to strain-relieve the SMT connectors somehow.

Cheers

Phil Hobbs

ENIG..

It's not quite that bad. Amphenol bulkhead connector with Kovar/glass seal, 31-4238,

is about $12 at digikey. The o-ring isn't the important part, the coaxial seal is what's hard to find.

$12 would be nice... Do you mean these?

~$22 for 100, still better than $50.

George H.

Hey, that's not the price I saw: OH, I typoed, I was looking at 31-4237, and the drawings link is a bit broken, but it seems to be only a crimp-seal, not glass/metal.

TTIinc has the 31-4238 part listed at $17.22 for qty 25...

There's at least one commercial mass-production use still

but as for retail-item support... I dunno.

I was joking. mini-din is the worst connector ever created.

LOL, and here I was thinking WTF? Mini DIN?

On Wed, 17 Jun 2015 12:56:47 +0800, just_me Gave us:

Limo at $40 per pin.

Lemo are very nice but a bit of a prick to assemble (as well as expensive).

Limo connectors, that's about it. Nice one.

Cheers

Phil Hobbs

Oh, You need to add the smiley face for me then... I'm fairly gullible. What's wrong with the mini DIN? We use some with little desk top power supplies.

George H.