| Author |
 Topic  |
|
|
halcyonrichard
United Kingdom
20 Posts |
 Posted - 04 Sep 2025 : 13:18:39
|
Hi I have been asked by a customer to place a circular plated through pad on the edge of the PCB. i.e. the board outline will cut through the pad and only one half of it will remain. He wants to do this to solder wires to the edge of the PCB. Is it possible to do this ? Has anyone done a similar thing ?
Richard
Richard |
|
|
edrees
United Kingdom
802 Posts |
Posted - 04 Sep 2025 : 13:53:12
|
Yes, been there, got the T shirt & hat.
Just place the thru-plated hole on the edge of the pcb outline, but tell your manufacturer that it is a Castellated hole just to make sure.
Some Chinese proto pcb companies will, unfortunately, throw it out as an error.
Make sure that the pad is big enough as the pcb profile router bit can tear the plating away on anything smaller than say a 1.1mm pad diam. & 0.8mm diam. hole. |
 |
|
|
Peter Johnson
United Kingdom
515 Posts |
Posted - 04 Sep 2025 : 14:25:11
|
| All very valid, but you CAN use a semicircular pad. Set the pad style to use 'Offset Bullet' then make the length half the width. That's not normally allowed but this case is a special one. You'll end up with a semicircular pad so it needn't overlap the board edge. |
|
|
|
edrees
United Kingdom
802 Posts |
Posted - 04 Sep 2025 : 14:29:50
|
| Very sneeky Peter! Leant something new today again! |
|
|
|
halcyonrichard
United Kingdom
20 Posts |
Posted - 04 Sep 2025 : 17:25:27
|
quote:
Originally posted by Peter Johnson
All very valid, but you CAN use a semicircular pad. Set the pad style to use 'Offset Bullet' then make the length half the width. That's not normally allowed but this case is a special one. You'll end up with a semicircular pad so it needn't overlap the board edge.
Thanks Peter your a star  that works a treat.
Richard |
Edited by - halcyonrichard on 04 Sep 2025 17:26:15 |
|
|
|
halcyonrichard
United Kingdom
20 Posts |
Posted - 08 Dec 2025 : 14:39:07
|
Thanks for all the info. The customer had boards made all OK. But....
Now wants the pad lengthened so we have half a hole on the PCB edge but the pad is extended into the PCB. Which I can do by using an oval pad and having only half on the PCB. This leaves half the PAD hanging off the PCB. Or is there another way...
Richard |
|
|
|
edrees
United Kingdom
802 Posts |
Posted - 08 Dec 2025 : 16:09:37
|
| I see that Peter's suggestion/exception (length =half the width) doesn't work for offset ovals, so I think (at least for the meantime)) you're stuck with copper (1/2 pad) over the edge of the pcb,.... unless Peter has another sneeky suggestion? |
|
|
|
edrees
United Kingdom
802 Posts |
Posted - 11 Dec 2025 : 12:39:04
|
Richard,-
You could add a suitable rectangular copper pour area alongside the existing pad (on Top & Bottom layers). Then add a Top & Bottom solder resist rectangular "filled shape" area superimposed on the rectangular copper pour areas. This way you are effectively creating two pads that physically "clash" but will not throw up a Design Rule error. |
|
|
|
halcyonrichard
United Kingdom
20 Posts |
Posted - 11 Dec 2025 : 13:34:38
|
Sounds a good idea. I will give it a go.
Thanks
Richard |
|
|
|
Peter Johnson
United Kingdom
515 Posts |
Posted - 15 Dec 2025 : 10:15:21
|
| That's true, my suggestion won't work with offset ovals as it's a specific exception in the code for bullet pads to be able to get a semi-circular pad. It was intended both for this situation and for when two 'D' pads are needed for a solder bridge link. It's exactly what's needed here. |
|
|
| |
Topic |
|
Via or PAD on PCB edge