PCB with PCIE card edge - Any tips? - Page 1
Forum section: electronics / general

author: kd6oji
author_rank: Contributor
timestamp: September 02, 2020, 09:51:28 pm
content: So I am in the process of creating a PCI card edge for a pluggable adaptor in one of my projects, the PCI-E x1 gives me 36 contacts in a rather compact connector.My dilemma is, do I need to include the shorting bar (which gives the DRC a panic attack) or will the board house (JLCPCB) do this on their side during their artwork generation? I have asked them but of course, got a less than ideal response (we are not good with board creation).I have the card edge created per the specs from my connector datasheet, and everything is lining up beautifully in the 3D mockup.

author: langwadt
author_rank: Super Contributor
timestamp: September 02, 2020, 09:55:11 pm
content: shorting bar ?

author: kd6oji
author_rank: Contributor
timestamp: September 02, 2020, 10:00:10 pm
content: It is part of the process for the ENIG step to gold plate the fingers, it is then ground off during the finish routing process so you don't wind up with everything shorted together after the fact.

author: langwadt
author_rank: Super Contributor
timestamp: September 02, 2020, 10:40:27 pm
content: Quote from: kd6oji on September 02, 2020, 10:00:10 pmahh yes, fingers need to be electro plated to get the thick hard gold. It isn't ENIG, ENIG doesn't use electricity but it is too thin for connectors

author: kd6oji
author_rank: Contributor
timestamp: September 02, 2020, 10:46:35 pm
content: either way, the process needs a common for all of the pins to be plated, and my question is still unanswered, or am I just overthinking this? I could always just send the board as is and see I suppose.

author: Bud
author_rank: Super Contributor
timestamp: September 02, 2020, 10:54:32 pm
content: Jlcpcb web site only have ENIG for gold fingers if i remember correctly. For electroplating there is higher price and you need to talk to them for that option. I would think they handle the technology on their side, you just send the design as it is.

author: langwadt
author_rank: Super Contributor
timestamp: September 02, 2020, 11:00:14 pm
content: Quote from: kd6oji on September 02, 2020, 10:46:35 pmhttps://jlcpcb.com//quote/pcbOrderFaq/Gold%20Fingers?_ga=2.81276247.1344353953.1599087448-844081666.1595957022&_gac=1.258806264.1599087448.Cj0KCQjwhb36BRCfARIsAKcXh6HuQZ0p7wcC1OW8XmWrCRs7ugowwZjmYrN6dtUKbh-7HuAhgC5m71oaAgd8EALw_wcBseems like jlcpcb doesn't really do "proper" gold fingers apart from the chamfer, the just default to ENIG if you choose gold fingers

author: kd6oji
author_rank: Contributor
timestamp: September 02, 2020, 11:04:27 pm
content: yes, their 'info' page is a bit ambiguous. I am probably stressing for nothing, just want it to be right the first time!

author: ebclr
author_rank: Super Contributor
timestamp: September 03, 2020, 12:24:44 am
content: Did you contact they, they are there to help you

author: kd6oji
author_rank: Contributor
timestamp: September 03, 2020, 11:28:17 am
content: yes, they were not helpful if you had read what I posted above.

author: asmi
author_rank: Super Contributor
timestamp: September 03, 2020, 02:10:44 pm
content: Quote from: langwadt on September 02, 2020, 11:00:14 pmThis is garbage, not gold fingers. ENIG is very thin and will wear off after a couple dozens of inserts/disconnects at best. It's only good enough if you plan to insert it once and leave it that way for the entire lifetime of a board.

author: langwadt
author_rank: Super Contributor
timestamp: September 03, 2020, 02:56:04 pm
content: Quote from: asmi on September 03, 2020, 02:10:44 pmI don't know if it is garbage, it is better than nothing for prototyping and pci connectors are not rated for much more than a few inserting either

author: c64
author_rank: Frequent Contributor
timestamp: September 13, 2020, 02:13:43 am
content: Another option for prototyping (and maybe for small quantities as well) is DIY gold electroplating. I haven't tried myself but seen few tutorial, looks quite simple. You buy two bottles of stuff (nickel and gold solutions) and apply them with brush (connected to power supply).And it will end up cheaper as well.P.S. Gold solution is usually a cyanide - poisonous even if just inhaled

author: bitter_mike
author_rank: Contributor
timestamp: September 16, 2020, 01:03:15 am
content: Quote from: c64 on September 13, 2020, 02:13:43 amIt's not as easy as you might think...brush plating is tricky and even if you get a decent looking deposit, making it adherent so that it survives the the 100s or 1000s of insertion cycles is yet trickier. Not impossible, but it's not like paint by numbers.

author: SerieZ
author_rank: Regular Contributor
timestamp: September 16, 2020, 03:09:42 pm
content: Quote from: langwadt on September 03, 2020, 02:56:04 pmSome Months ago I did a very simple Board which slots into PCI express (Its purpose is testing some Mainboard during Production).I neither used bevel nor did I get gold fingers and the Board so far has sruvived around 100 reinsertions.Id only get something this fancy if a Clients gets to see it or I expect a TON of Insertions otherwise the price is NOT worth it.Just my 2 cents on the subject.