Multilayer and put through holes - Page 1
Forum section: electronics / general

author: Nevo
author_rank: Newbie
timestamp: June 15, 2017, 08:34:17 am
content: Hey there,i'm new here and have a problem of course.I am designing a 8 Layer Board and want to have Put through holes. They should contact only on two Layer. For Example i made a picture.Im confused what to do. When i take a via and say Altium, it should be conected at Layer 1 and 2 for example, i get a buried or blind via. When i take a pad, i cannot say wich layer should be conected. Unfortunately the PTH have to going through copper between the Layer and i dont know how to cut out the copper or the pad at that postition.I used the function fill and solid region for the copper.By the way, the manufacturer wants to have a dimensional drawing. Can i draw the dimension on the mechanical layer and give it out with the gerber files?Greetings and thanks for your help.Frank

author: julianhigginson
author_rank: Frequent Contributor
timestamp: June 15, 2017, 09:18:12 am
content: you need to study up on plane connect rules, and track routing... I'm not sure where to start explaining what you don't know because this is some very fundamental missing the point of how altium works... if you can explain what you used before, maybe someone who understands both programs could help with a simple pointer on where your paradigm differs from how Altium works...also is this a brand new PCB design or have you picked up something that already exists and trying to edit it?

author: mrpackethead
author_rank: Super Contributor
timestamp: June 15, 2017, 09:28:56 am
content: What you are wanting does not exisit. You cant' run a via through a pcb that doe'snt connect to the layers it passes by.. Blind and buried vias are setup between specific pairs.. ( normally for example you can have them between the layer pairs ) 1-2, 3-4, 5-6, 7-8 the outside being blind and the inside ones being buried )... You can have those at the same time as having a via that goes all the way through.You need to know from yoru fab what their capability are, and then you need to set up the allowable via combinations..

author: Nevo
author_rank: Newbie
timestamp: June 15, 2017, 11:06:33 am
content: Quote from: julianhigginson on June 15, 2017, 09:18:12 amI dont know anything about the rules but i will study up them. This is my first PCB-Programm (i know Altium is a professional program, but we have it at the university and i need the odb++ file later)Its a brand new Design.Quote from: mrpackethead on June 15, 2017, 09:28:56 amOk. But how can i get a cutout from the copper at the right place, where the Via is going through and should not connect? At the moment i dont use the polygon pour. Can i define a cutout on another way from the fill or solid region command? Otherwise i have to draw round the vias, so they dont connect to the copper and that is not very comfortable. Hopefully you know what i mean.

author: mrpackethead
author_rank: Super Contributor
timestamp: June 15, 2017, 11:20:28 am
content: Quote from: Nevo on June 15, 2017, 11:06:33 amOk i understand what you are doing now.. You really dont' want to use Fills or solid regions for that, as you cant' assign them to a net. The Polygon pour is what you want to do.. If your via is in teh Net "MyNET', and the polygon pour is the the Net "GND", when you pour the polygon, it will automaticaly put a clearnace around the via.. That clearnace distance is setup in the clearance's in your design rules.

author: Nevo
author_rank: Newbie
timestamp: June 15, 2017, 11:57:01 am
content: Ahh...i got it.But there is a problem left. One Via should connect the first layer and the second layer. Another Via should connect the second Layer with the third layer. All have the same net and there is allways copper between. Now Altium would connect the Vias with the first, second and third layer. Do i have to define a net for every Layer? Where can i tell Altium which nets should be connected in the design rules?Can I use the fill command and the polygon pour similiar? The reason is I need a hugh radius but with the polygon pour i just get a small radius when I am switching it with shift and space. (Let me have a guess. In the design rules?)

author: free_electron
author_rank: Super Contributor
timestamp: June 15, 2017, 03:24:13 pm
content: you simply need to set up the from-to layer pairs.place a via. double-click it , then click layer pairs.

author: ManCave
author_rank: Regular Contributor
timestamp: June 22, 2017, 10:20:14 am
content: Why do you need to connect same net through two different TH pads across three (or more) layers (just out of cuirosity)?Drill pairs work for vias but will not work for pads as they are for through hole components. You wouldn't want to have a pad where component only inserts half way down the hole and then hits a fibreglass...There is a way I can think of (while I still don't understand why you would do it in the first place) is to use keepout Arc around the pad on the layer where you don't want connection to your polygon. If it's just one out of 8 layers, and only a few connections, this could be a cost effective way of doing it. Go Place->Keepout->Arc and place it around the pad you don't want to connect to the plane. Configure the keepout so that it is placed on the layer where the polygon is. Make sure that "TH pad" is not ticked otherwise you get DRC error (see image below). You can see the result on the image below.....but why?