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geekhack Projects => Making Stuff Together! => Topic started by: shadewind on Tue, 06 August 2019, 09:00:08

Title: PCB fabs and pad/hole overlap
Post by: shadewind on Tue, 06 August 2019, 09:00:08
I'm designing a PCB and am considering using JLCPCB to manfacture it. However, in my current design, I inevitably end up with overlapping pads and holes. Specifically, these cases:


Does anyone have experience with this with JLCPCB or other PCB services for that matter? Any special care that needs to be taken? Special instructions? Things to avoid? Workarounds? Fabs to prefer over others?

Intuitively, case 1 and 2 seems like they should be unproblematic as longs the gerbers are not misinterpreted by the factory. Number 3 seems like it could cause issues since you need to drill through a plated hole, could this cause issues?
Title: Re: PCB fabs and pad/hole overlap
Post by: SneakyRobb on Thu, 08 August 2019, 11:34:18
In my experience Jlcpcb is good at telling you exactly what they like, don't like, and if they don't like it how much extra it will cost you. Or they will say please redesign.

You really just need to send an email to support asking them about these 3 options.

Also you say you need overlapping pads and holes. Is this really set in stone? can you post an example of why this arrangement is necessary?
Title: Re: PCB fabs and pad/hole overlap
Post by: shadewind on Thu, 08 August 2019, 13:45:18
Quote from: SneakyRobb on Thu, 08 August 2019, 11:34:18
In my experience Jlcpcb is good at telling you exactly what they like, don't like, and if they don't like it how much extra it will cost you. Or they will say please redesign.

You really just need to send an email to support asking them about these 3 options.

Also you say you need overlapping pads and holes. Is this really set in stone? can you post an example of why this arrangement is necessary?

To be honest, I don't really need anything since I'm mostly doing it for myself. I'm emulating the layout options in the KBD75 and this makes the ISO/enter/backpace area end up like this:
https://www.dropbox.com/s/sobk6rpj5uocryd/padholeoverlap.png?dl=0

As you can see, one of the pads of net ROW3 overlaps with one of the stabilizer holes for the ISO return key. This is just one example.

But thanks for the information about JLCPCB. In the end, if there's any trouble I'm probably just going to ditch multi layout this time around but it's interesting to know how people do it.
Title: Re: PCB fabs and pad/hole overlap
Post by: gorbachev on Sun, 11 August 2019, 19:38:46
My experience with ALLPCB is that they will flag it, ask you about it and then you can tell them "it's by design", and they'll happily fabricate it. It will delay the manufacturing by about 2 days, though.