Polygon pours on internal layers - Page 1
Forum section: electronics / general

author: Posh
author_rank: Contributor
timestamp: September 02, 2019, 05:40:04 am
content: Hey all,I have been struggling for a few hours to get polygon pours to appear on the internal layers of my four layer PCB.Polygon pours are working perfectly on the external (top and bottom) layers, and I can see the copper in 3D mode.On internal layers, the polygons will not fill when within the board region - and the copper does not appear in 3D.If I move the polygon on an internal layer to outside of the board region, It will pour just fine...I have considered using 'plane' internal layers, but would prefer to stick with signal layers for their flexibility. My layer stack-up settings are in the image.I'm pretty stumped by this - any advice would be appreciated!

author: pigrew
author_rank: Frequent Contributor
timestamp: September 02, 2019, 05:52:51 am
content: Some ideas that come to mind:There are no existing objects on the inner layers on the particular net, and you asked it to "remove dead copper" in the properties of the polygon.In the design rules, the board edge clearance is set very high (wider than your board's size), so the polygon is illegal.Polygon net is set to "None".A lot of the options can be set in the Polygon Manager. Perhaps post a screenshot of that, showing the properties of the polygon that's at fault?

author: Posh
author_rank: Contributor
timestamp: September 02, 2019, 06:10:38 am
content: Thanks for the ideas, I've attached an image of the Polygon ManagerI haven't added any objects to the inner layers - there are only the multi-layer vias and through-hole pins.My polygon edge clearance is 0.25 mm, which seems to be working on the external layers.My polygon net in this example is set to GND, the other two polygons I am working with have their respective nets.

author: Psi
author_rank: Super Contributor
timestamp: September 02, 2019, 06:26:19 am
content: Do you have power/ground available on the inner layer for the polygon to pour from?It wont pour if there's nothing to pour from.Also check that you don't have some weird polygon clearance rule that keeps it from getting close enough to GND vias to connect to them.You will get problems if you have GND on the internal layer but the polygon pour cant get close enough to touch it due to a rule.As a test, disable the "remove dead copper" tickbox for the polygon pour and re-pour it.See if you get copper on inner layers then.The problem may become obvious, like the polygon might be avoiding touching your GND via and so is dead copper and being removed. etc..

author: Posh
author_rank: Contributor
timestamp: September 02, 2019, 06:47:04 am
content: I should have power/GND to pour from, as I have ground pins/vias on the ground net coming through the layer - Just in case I dont, I added a GND pad to the layer.I checked the PlaneConnect, PlaneClearance and PolygonConnect rules - I don't see anything out of shape, and these rules work fine for pouring on the external layers.I've been testing with 'remove dead copper' checked and unchecked without change.Attached is a screenshot showing the GND polygon and the nets available.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 02, 2019, 08:06:03 am
content: Is auto repour disabled? You've been manually repouring, right?Tim

author: Psi
author_rank: Super Contributor
timestamp: September 02, 2019, 08:16:19 am
content: If you want to post/PM your files i will have a look

author: Posh
author_rank: Contributor
timestamp: September 02, 2019, 10:19:43 am
content: Quote from: T3sl4co1l on September 02, 2019, 08:06:03 amI've been manually repouring with 'Repour Selected' or 'Repour All'Quote from: Psi on September 02, 2019, 08:16:19 amI don't mind PM-ing them, i'll send them through in a few hoursThanks for the help guys

author: tszaboo
author_rank: Super Contributor
timestamp: September 02, 2019, 11:28:20 am
content: If you dont have traces on the inner layers, then use the inner layers as planes. Lot simpler. It works in inverse.Only use signal layers for the inner layer, if you really really run out of space on the top and bottom.

author: Psi
author_rank: Super Contributor
timestamp: September 02, 2019, 12:20:23 pm
content: I prefer all signal layers. Power planes can get annoying when pcb houses have to deal with inverted layers.The OP should be able to work with polygon pours on the inner layers exactly the same as the outer layers.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: September 02, 2019, 09:51:26 pm
content: In fact I did a design recently, 8 layers ~1k components, and the constant recalculating inner planes when moving any hole/via/pad was disgusting (~2 sec). Changed to polygons, no problems. I mean, repour is even slower (a minute), but that's done in batch, much more tolerable.Tim

author: langwadt
author_rank: Super Contributor
timestamp: September 02, 2019, 10:02:23 pm
content: Quote from: Psi on September 02, 2019, 12:20:23 pmwhat really the point of using power planes any more? it's not like making it easy to do with tape is something thathas been a concern for the last many decades

author: Psi
author_rank: Super Contributor
timestamp: September 02, 2019, 10:29:46 pm
content: Quote from: langwadt on September 02, 2019, 10:02:23 pmexactly

author: Posh
author_rank: Contributor
timestamp: September 03, 2019, 04:34:33 am
content: After my friend and I played around with the board for a few hours, we finally got it to work!The issue was quite obscure - The layer stack manager had multiple 'Board Layer Stack' configurations, which seemed to be conflicting with one-another. After removing the duplicates everything pours fine.I am not sure how these duplicates appeared, I'd never even seen this drop-down before... to make it appear you have to enable 'Rigid/Flex' under the 'Features' drop-down. From there you can delete the duplicates by selecting them and then clicking the bin.Certainly a frustrating issue to troubleshoot!Thanks for the help

author: tszaboo
author_rank: Super Contributor
timestamp: September 03, 2019, 07:56:07 am
content: Quote from: langwadt on September 02, 2019, 10:02:23 pmThat you double click on a layer, and set it to be a net, and you are done with it. If you polygon pour it, you have to babysit the layer with repoiring it continuously, set via connection styles and so on. It is just so much easier. If you have a large board, repour can also take serious amount of time.And I never seen a PCB manufacturer, who didnt immediately realised when they saw a plane. Besides, you send a stackup legend, so define it if you really need to.

author: Psi
author_rank: Super Contributor
timestamp: September 03, 2019, 08:37:13 am
content: Quote from: NANDBlog on September 03, 2019, 07:56:07 amYes that's true.If you're doing a large 8+ layer pcb i can imagine the re-pour time would be longer.But time to pour a polygon layer is proportional to how complex the layer is. A layer with nothing on it expect the polygon fill should re-pour pretty fast.

author: thm_w
author_rank: Super Contributor
timestamp: September 03, 2019, 07:56:19 pm
content: Join the pleb world, for people without supercomputers we shelve polygon pours to avoid recalculating until you are close to finishing the layout.btw, you can define the PCB shape in the keepout layer then no wild polygon shapes are needed to match the board (just make a big oversize square). But not much of an advantage until you are re-sizing/re-drawing the board shape.

author: Pseudobyte
author_rank: Frequent Contributor
timestamp: September 03, 2019, 08:23:11 pm
content: Quote from: thm_w on September 03, 2019, 07:56:19 pmOr in the polygon manager you can create a new polygon from the board shape

author: Psi
author_rank: Super Contributor
timestamp: September 03, 2019, 11:45:00 pm
content: Quote from: Pseudobyte on September 03, 2019, 08:23:11 pmyes, if you don't know about this, learn about it now.So much easier.

author: ajb
author_rank: Super Contributor
timestamp: September 06, 2019, 08:14:41 pm
content: Quote from: thm_w on September 03, 2019, 07:56:19 pmOr just enable a Board Outline Clearance rule (under manufacturing rules). I think that rule became available in AD17 or AD18? That works from the actual board outline definition, so it always responds to changes in board shape (including board cutouts), with no need for any keepout primitives.

author: thm_w
author_rank: Super Contributor
timestamp: September 06, 2019, 09:14:30 pm
content: Quote from: ajb on September 06, 2019, 08:14:41 pmOK thats definitely the way to go, it seemed like they were deprecating keepouts as they are difficult to work with now. thanks.