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From: John R Walliker <jrwalliker@gmail.com>
Newsgroups: sci.electronics.design
Subject: Re: Feedthough/via that straddles (i.e., is bisected by) the cut edge
 of a PCB?
Date: Wed, 29 May 2024 18:23:35 +0100
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On 29/05/2024 15:56, john larkin wrote:
> On Wed, 29 May 2024 05:55:24 -0700, Don Y
> <blockedofcourse@foo.invalid> wrote:
> 
>> I can't see any way to do this, reliably.  So, imagine a house won't
>> let it through DRCs, regardless of diameter or weight of foil, etc.
>>
>> Or, is there another (not exhorbitantly pricey) technology for precisely
>> cutting boards that would keep the structure (at least the part that is
>> not lost to the cut) mechanically (and thus electrically) intact?
>>
>> Else, I will use another -- more expectantly reliable -- approach
> 
> It's called castelleaton, or mouse bites. I do it fairly often. Works
> fine.
> 
> Our PCB houses don't like the drill to be any smaller than 16 mils.
> 
> https://www.dropbox.com/sh/te3csdd2mlszvfe/AAAnJ5c8DMAJPQkwWbN3FeNra?dl=0
> 
I recently had a few hundred small adapter boards made by a UK
manufacturer with plated castellated edges.  The finished hole diameter 
was 0.7mm, board thickness was 0.8mm.
The only problem was that the part of the hole that was meant to be
cut away remained partly in place as a copper burr.  I did need to
trim these away with a scalpel.  The manufacturer had warned me that
this would probably happen and would only make the boards on that
basis.  Larger holes would have been fine.
John