topic Re: Airwire on pin that is part of polygon pour in Fusion Electronics Forum

Airwire on pin that is part of polygon pour

jvlob — Tue, 10 Sep 2024 14:59:26 GMT

Hello everyone!

I’m really stuck on an issue with a missing airwire in my design. Here’s the situation:

• I have a polygon pour on both the top and bottom layers for the +V signal.

• I’ve also added via stitching to connect the top and bottom layers at multiple points.

• My design includes several common anode LEDs, with their anodes connected to +V. All of the LEDs are working perfectly except for one.

For some reason, one of the LEDs still has a missing airwire, and I can’t figure out why:

Even if I unroute everything, that airwire is still there, only on that LED:

• There are two vias near this LED, and everything seems to connect to +V through the polygon pour.

• I’ve checked, but I must be missing something obvious that I’m just not seeing.

Any help or suggestions would be greatly appreciated!

Thanks in advance!

Re: Airwire on pin that is part of polygon pour

jorge_garcia — Tue, 10 Sep 2024 20:28:42 GMT

Hi @jvlob,

I hope you're doing well. Once you ripup everything, there is no interaction between the top and bottom layers so an airwire there would make a lot of sense. Without a picture of the routing on the top it's hard to find the gap, these types of airwires usually prop up if there is a gap or island of copper.

Look carefully, in the worst case all you have to do is manually route one airwire.

Let me know if there's anything else I can do for you.

Best Regards,

Re: Airwire on pin that is part of polygon pour

jvlob — Tue, 10 Sep 2024 20:43:36 GMT

Hello @jorge_garcia and thanks a lot for your reply.

What I'm not understanding is why there is only that airwire on that specific LED (given that there are 4 more LEDs with the same configuration and no airwire on them). The whole polygon pour in both layer is that signal (+V).

Here you can see a screenshot with all layers visible:

Since I posted I have redone the routing a couple of times trying to figure this out and for some reason now the LED with the airwire is the one on the right, but it is the same problem.

Here you can see the via stitching properties with the signal +V.

I could solve this "error" by connecting that +V of the LED to the battery +V through a via but I want to understand why this is happening because I don't find the reason, if the top and bottom layer has a polygon pour of the signal +V and they are connected together through via stitching... I don't know.

Thanks again for your time 🙂

Re: Airwire on pin that is part of polygon pour

jorge_garcia — Wed, 11 Sep 2024 18:49:13 GMT

Hi @jvlob,

Don't let the location of the airwire distract you. Whenever islands occur, a single airwire will appear indicating that the islands are disconnected. Usually the gap or the break is in the area of the airwire, it can be on the top or on the bottom layer or some mix of both. The stitching can help, but it's not a guarantee because you may have gaps or areas where the stitching doesn't occur. In this design, the battery holder takes up a lot of space if the islands occur on the bottom layer underneath that battery holder the stitching won't help at all.

If you want to go through this exercise, here is what I would do. First look at the top layer only. Identify if there are any islands of copper (disconnected areas in the polygon pour). Repeat the process for the bottom layer. The stitching will connect islands on top and bottom but the gaps will remain on the same layer. I can't see the bottom layer very well in your picture but it seems like the problem will be on the bottom layer of this routing attempt.

Let me know if there's anything else I can do for you.

Best Regards,

Re: Airwire on pin that is part of polygon pour

jvlob — Wed, 11 Sep 2024 19:08:49 GMT

Hello again, @jorge_garcia, and thank you for your input.

I’ve been really trying to understand the problem, but I’m struggling to do so. 😞

I’ve removed all other traces connecting components and left only the top and bottom copper pour (+V) and via stitching (+V). From what I understand, +V should cover both the top and bottom layers, and both layers are connected with no islands, but I might still be missing something.

I recorded a short video showing both layers individually, the signals on each copper pour, and the via stitching. Hopefully, you can spot something wrong there. If not, I guess I’ll just go for a trace-via-trace connecting the battery +V signal to the LED, but it bothers me that I don’t understand what I’m doing wrong.

(view in My Videos)

Re: Airwire on pin that is part of polygon pour

jorge_garcia — Wed, 11 Sep 2024 19:56:47 GMT

Hello @jvlob,

Here's is something to try. Make sure top and bottom are on, unfill the polys and then refill them. Do they look correct?

My gut feeling is that the airwire will still be there. If that happens try this, rout from V+ pad on the battery connector and drop to the bottom layer. Leave just the via and connect and refill the poly gone. Does the airwire go away?

My theory is that the via stitching isn't clearing the airwires. This manually routed via drop should consume the airwire. If this works then it might definitively prove that the via stitch isn't consuming the airwires.

Best Regards,

Re: Airwire on pin that is part of polygon pour

jvlob — Wed, 11 Sep 2024 21:21:26 GMT

Thanks again for your help! I believe this is exactly what was happening, as I was able to eliminate the airwire by following your advice.

Shouldn’t the via stitching have cleared the airwires? In any case, I now have a better understanding and can move forward.

I really appreciate your assistance!

Re: Airwire on pin that is part of polygon pour

jorge_garcia — Thu, 12 Sep 2024 17:09:51 GMT

Hi @jvlob,

I'm happy to have helped. This should be fixed.

@panpan_fan I saw that you posted on another via stitching thread. Would you be able to to check this issue and possibly write a ticket for it?

Thank you in advanced.

Best Regards,

Re: Airwire on pin that is part of polygon pour

jvlob — Thu, 12 Sep 2024 18:38:32 GMT

If there’s anything I can assist with regarding this issue, feel free to reach out.

Thanks!

Re: Airwire on pin that is part of polygon pour

panpan_fan — Fri, 13 Sep 2024 02:34:06 GMT

Hi @jvlob @jorge_garcia

Thanks for reporting this issue!

I have a quick try and I can't reproduce it easily.

@jvlob Would you mind sharing your file to us?

I will send my email to you as a private message

Regards,

Panpan Fan

Re: Airwire on pin that is part of polygon pour

panpan_fan — Fri, 13 Sep 2024 02:47:17 GMT

Hi @jvlob

Sorry I didn't noticet that you have the led in the bottom layer.

I can reproduce it now. You don't need to send your file to us.

And I report it to the develop team to check this issue.

Regards,

Panpan Fan

Re: Airwire on pin that is part of polygon pour

panpan_fan — Tue, 19 Nov 2024 03:27:40 GMT

Hi @jvlob

I hope you are doing well!
Today we release Fusion V2.0.20754 and this issue should be fixed now.

Please have a try, thanks a lot!

Regards,

Panpan Fan