Seeed have emailed me today about a gerber I sent where one of the vias has no pad on it. I was wondering if there’s a rookie mistake I’ve made in KiCad that I can look out for.
as the picture shows about the hole, there is no pad on it. If we slot the hole, it may cause short
circuit. Could you please help me check?
In pcbnew when I compare it with another via on the board it says (other than the particular name and net number) they’re the same so far as I can tell.
My plan is to delete that track, re-route and re-export but it’s not much of a plan granted I don’t kwow what could have caused this. Any ideas?
e[quote=“Dolganoff, post:3, topic:652, full:true”]
What are your settings for via size and via drill?
[/quote]
I was just running on the defaults. It says track 0.254mm (10.00 mils) with vias 0.89mm (35.0 mils). 0.889mm is what the specific via says when you select it in pcbnew. The info across the bottom when selected says Type Through Via, NetCode 21.1, Status . . (two dots), Layers F.Cu/B.Cu, Diameter 0.889, Drill (default) 0.635mm, Length 32.733mm, NC Name Default, NC Clearance 0.254mm, NC width 0.254mm, NC Via Size 0.889mm, NC Via Drill 0.635mm.
Another via nearby I chose had all the same dimensions, but NetName, NetCode and Length are different.
@JoeChen had you seen this issue before when the ‘do not tent vias’ wasn’t used?
Thanks guys - very much appreciate your advice,
Geoff
As far as I understand it, “do not tent” option applies only to solder mask layer, and should have no impact on copper rendering (like via pads).
@stryker, what does Kicad’s Gerber viewer show? Does it show pads around vias?
I see your via drill is rather big compared to via pad size, you’re getting only (0.89-0.635)/2=0.12 mm of copper around the drill. Depending on what drill diameter step the fab uses, you may end with the drill as big as the pad.
You can try to reduce via drill, I’d suggest you to consult your fab house on what dril diameters they support and recommend.
Your vias spec looks OK to me, since I also used the same Kicad defaults with my PCB design. I had my PCB fab’ed through DirtyPCBs.com, and the boards came back OK, with the vias being copper plated, though under a scope the vias seems to not have enough pads around.
However, for the next new PCB design, I’ll reduce the via drill size while keep the same 35 mil via size.
I do not see any issues with it, but the vias of my PCB are not solder tinned, or solder plated, causing a scare to me. Luckily all vias are working as expected. But, I will use option of ‘do not tent vias’, hopefully to get them tinned the next time.
Sorry have been away but finally got around to checking this. And it appears that the via without the plating has been exported differently to the others.
In this screen grab from the KiCad gerber viewer with just L1 and L2 copper selected, the one marked D25 has a round disc of copper on both layers. The one that Seeed has called out as faulty has no disc on either layer.
Is this something I have inadvertently done to the via in pcbnew ?
Sorry for the posts in quick succession - but there is something odd going on here. That misformed via is on a track that stays on the bottom copper - there’s no transition from top to bottom there. I re-exported the gerber and it created a drill on that corner again so it’s something that KiCad believes needs a drill hole. There’s no white dot representing a via on the board there though at all.
So, I deleted the track and laid it again on the bottom copper as before, saved and exported the gerber and no additional drill hole is there now.
Unfortunately the mystery of the unplated via ends without the true culprit being identified. But it is a story with a happy ending.
