Slots in planes - how?  [Protel] - Page 1
Forum section: electronics / general

author: DTJ
author_rank: Super Contributor
timestamp: December 16, 2015, 12:04:13 pm
content: I'm trying to put a 20mil slot through all layers on a 4 layer board using Protel 99SE.This is not a physically milled / routed slot, just an "electrical" slot in the copper on all layers 20mil wide and say 50mm deep/long.Top layer is signal tracks + ground pour.1st inner layer is gnd.2nd inner layer is pwr.Bottom layer is signal + ground pour.A keep out line wont work as it only applies to the top/bottom layers.I looked at placing a spit poly plane where the slot needs to go but it needs a net & introduces a floating strip of Cu.Silly question - how do I do it?Cheers.

author: jmarkwolf
author_rank: Regular Contributor
timestamp: December 16, 2015, 02:13:52 pm
content: If I understand your question properly, you need a "slot shaped" void in your plane layers.Do this simply by placing a track of the desired width, length and location on your plane layer.Since the plane layers are ultimately a "reverse" image relative to the signal layers, any track (or other entity) on the plane layers will become a "void" in the copper of the plane layer.

author: free_electron
author_rank: Super Contributor
timestamp: December 16, 2015, 03:22:20 pm
content: draw a line on the keepout layer in that area. set the line width to 1 mil and write a rule to stay away the desired amount of space.

author: DTJ
author_rank: Super Contributor
timestamp: December 17, 2015, 01:46:10 am
content: Thanks for the replies guys.jmark - I can see that working but won't it leave a floating unconnected track?free_electron - will a line on the keepout layer work? Doesn't the keepout layer only apply to tracks and components on the outer (top and bottom) layers?

author: langwadt
author_rank: Super Contributor
timestamp: December 17, 2015, 01:57:50 am
content: Quote from: jmarkwolf on December 16, 2015, 02:13:52 pmin the old days planes were basically just a reversed image of the pads, does anyone still do planes in reverse?These days I don't see any reason to not treat all layers as signal layers, some of them just being mostly flood filledwhat you draw is what you get

author: DTJ
author_rank: Super Contributor
timestamp: December 17, 2015, 03:54:57 am
content: langwadt - yeah I'd thought about that approach. You've given me some confidence.As it is the inner layers are all set up as a single net (gnd or pwr). I can see a way to do the slot is to not assign the layer to a net and to just pour a poly with a slot in it and assigned it to the net that I want.I hope that makes sense!

author: free_electron
author_rank: Super Contributor
timestamp: December 17, 2015, 03:55:30 am
content: Quote from: DTJ on December 17, 2015, 01:46:10 amkeepout is keepout. it should work on planes as well

author: DTJ
author_rank: Super Contributor
timestamp: December 18, 2015, 01:29:02 pm
content: free electron,Yep that's what I reckon it should be, so keepout should work.I've tried the "paint what you want" split plane approach and it works.I'll try the keepout track approach and see what it looks like with the gerber viewer I've downloaded.Cheers.

author: jmarkwolf
author_rank: Regular Contributor
timestamp: January 07, 2016, 01:01:57 pm
content: Quote from: DTJ on December 17, 2015, 01:46:10 amSorry for the delay in response. Was out of town.Placing a track on a plane results in a "void" in the Gerber file. No "floating unconnected tracks". Try it, generate a Gerber set and look.