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From:
"Decker, Scott Collins" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Decker, Scott Collins
Date:
Thu, 22 Aug 2019 22:25:18 +0000
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Steve,

    When you replied, I realized I was thinking press fit for hardware and not the connector’s themselves, I had that Duh moment and, well, dropped my head on the keyboard in shame… :-/  I digress. Anyway, I believe as long as you have proper tooling for the pins, they should press OK. (Might want to drill a bit larger depending on the number of pins in the connector), but I would agree that a manufacture might have better data on thickness minimums and such. My thought would be if it’s higher density, (.050” pitch) it might not work out to well but maybe a .100” pitch or more field would be just fine. Sorry for the misleading answer, but if you ever need to put a Pem nut in, there you go! ☺

Later…



Scott Decker | Senior Engineer, PCB Design Services CID+ | Electronic Systems Center

COLLINS AEROSPACE

3445 S. 5th Street, Suite 170, Phoenix, AZ 85040 U.S.A.

Tel: 602 308 5957  FAX: 602 243 2347

[log in to unmask]<mailto:[log in to unmask]>  www.collinsaerospace.com<http://www.collinsaerospace.com>



CONFIDENTIALITY WARNING: This message may contain proprietary and/or privileged information of

Collins Aerospace Systems and its affiliated companies. If you are not the intended recipient please 1) do not disclose, copy,

distribute or use this message or its contents, 2) advise the sender by return e-mail, and 3) delete all copies (including all

attachments) from your computer. Your cooperation is greatly appreciated.



From: Steve Gregory [mailto:[log in to unmask]]

Sent: Thursday, August 22, 2019 2:50 PM

To: Decker, Scott Collins <[log in to unmask]>

Cc: TechNet E-Mail Forum <[log in to unmask]>

Subject: Re: [External] [TN] Minimum PCB thickness for press-fit technology?



Hi Scott,



Thanks for the feedback. These will be connectors, I don't know what manufacturer is so I can't dig into a datasheet to learn what PCB sort of spec's will be required. I'm doing a budgetary quote for some boards that haven't been designed yet. The customer is asking for some very rough labor numbers based on a general description of the PCBA like: 150 single-sided SMT components, 5 through hole connectors, 4 press fit connectors, 6-layer, 5" X 8",  .031" thick PCB. When I saw the press-fit and .031" thick PCB is what got my attention. I've never pressed any connectors into a board that wasn't at least .062" thick...



Steve



On Thu, Aug 22, 2019 at 3:37 PM Decker, Scott Collins <[log in to unmask]<mailto:[log in to unmask]>> wrote:

Steve,

  I think the answer is, "it depends". We have a rigid-flex board that is .093" thick and had issues with press fit nuts, but ended up increasing the hole size a tiny bit to lessen the force required to press the nuts in. We had a supplier using a 5 ton hydraulic baring press to do the pressing and they promptly delaminated the boards. (That was not needed to press them either, you could do it with a pair of pliers almost.) Ouch!

   Anyway, I have done .031" boards in the past and used Pem nuts in them just fine. Just take note that they recommend different hole sizes for PCB versus sheet metal, etc. That said, in our case, increasing the hole size slightly, prevented the board from getting damaged during the press operation. The key to watch is the press section of the nut/spacer, and that it's not any longer than the board thickness.

I've done both plated and non-plated holes and had good results in both cases so plating wasn't an issue in my cases at least. I would suggest that if you do plate the holes, don't use HASL for the finish, that will cause issues sometimes. In all cases too, the compression mode was to pull the nut into the PCB and not push it away/out. In the case of the .093" board, the press was just enough to hold the nut in during assembly and a few on off cycles so we've not had any issues with the larger hole size. Don't know if this helps or not, but...

Later...



Scott Decker | Senior Engineer, PCB Design Services CID+ | Electronic Systems Center

COLLINS AEROSPACE

3445 S. 5th Street, Suite 170, Phoenix, AZ 85040 U.S.A.

Tel: 602 308 5957  FAX: 602 243 2347

[log in to unmask]<mailto:[log in to unmask]>  www.collinsaerospace.com<http://www.collinsaerospace.com>



CONFIDENTIALITY WARNING: This message may contain proprietary and/or privileged information of

Collins Aerospace Systems and its affiliated companies. If you are not the intended recipient please 1) do not disclose, copy,

distribute or use this message or its contents, 2) advise the sender by return e-mail, and 3) delete all copies (including all

attachments) from your computer. Your cooperation is greatly appreciated.



-----Original Message-----

From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]>] On Behalf Of Steve Gregory

Sent: Thursday, August 22, 2019 1:05 PM

To: [log in to unmask]<mailto:[log in to unmask]>

Subject: [External] [TN] Minimum PCB thickness for press-fit technology?



Hi all!



I thought I'd throw the question out there while I'm google-ing for it, is there a minimum PCB thickness that you would want to use press-fit technology? I'm thinking it's .062", I think I read that somewhere, now I'm trying to find it. But a .031" thick PCB seems too thin. Thoughts?



Steve



--

Steve Gregory

Kimco Design and Manufacturing

Process Engineer

(208) 322-0500 Ext. -3133



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--

Steve Gregory

Kimco Design and Manufacturing

Process Engineer

(208) 322-0500 Ext. -3133



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