IMS PCB

[tszaboo]

Has anyone worked with IMS PCBs in Altium? I just tried to set my core to anything else than FR4 in the layer stack manager, but I would only find FR4. is it just me not finding it or do I have to import something to have the stackup possible? Has anyone used/downloaded  design rules?

[maxpayne]

I am sorry but what is IMS ?

[tszaboo]

I am sorry but what is IMS ?

Isolated Metal Substrate. It's a common name for Aluminium or Copper core PCBs.

[mikeselectricstuff]

What is the reason you need the PCB tool to be aware of the substrate type - controlled impedance etc.?
 

[tszaboo]

It's a good question. Not impedance.
Design rules for one. By the looks of it, I cannot even make a PCB single sided. So if I place a plated hole...
The second part is the documentation. I regularly use Draftsman to generate doc. for regulatory purposes. That includes stackup.

I know I can just design a board with only drawing on top layer, and create my stackup in MS Word, but I expert this to just work for the money I'm paying. For sure I'm not the first one who wants to design an Aluminium PCB in this software. By the looks of it, there is only FR4, so not even CEM or Phenolic PCBs.

Or I just don't know where to click.

[Kean]

I've done a few LED PCBs on aluminium core MCPCBs.  Single layer, 20-30W, 200-240mm dimensions.
When I'm in the office tomorrow I can check how I set up my layer stack.

[Kean]

Sorry, I recall looking at this for similar reasons but it appears I just wanted to get the designs done and I left the layer stacks as 2 layer 1.6mm FR4.

I recall turning off stack symmetry, but then could not find any option for adding an alternate core material.  I'm not sure I even found a way to set a single layer, or remove the ability to add vias.

I am using AD19, so maybe you have more options under Tools -> Material Library in a newer version.  You can add custom core and prepreg definitions, but they assume standard materials.  Or maybe newer versions have something under Tools -> Features where I have options for Printed Electronics and Rigid/Flex, but no IMS.

There are a bunch of posts about IMS (MCPCB) on the Altium resources blog, but they are all about how wonderful Altium is and it can help with MCPCB, but with no actual example or guidance shown.

[Pseudobyte]

The biggest things you need to worry about are:

• Hole to Hole Clearance
• Copper to edge/NPTH Clearance
• Largest drilled hole before it becomes a routing operation

You need to make sure you are allowing space for the manufacturer to over size all the plated through hole and still leave a sufficient web in the Aluminum/Copper core. They back fill the holes with a non-conductive epoxy and then drill the actual PTH in the epoxy.

[thm_w]

It's a good question. Not impedance.
Design rules for one. By the looks of it, I cannot even make a PCB single sided. So if I place a plated hole...
The second part is the documentation. I regularly use Draftsman to generate doc. for regulatory purposes. That includes stackup.

You can use a plated hole, as Pseudobyte says. Of course that raises the manufacturing cost a lot, so you likely don't want it.

But placing plated holes is still fine on a single layer alu PCB, the manufacturer will just drill them as normal holes with minimal clearance (JLC). There are valid reason to want to do this.
I'm sure you could set up some design rule for PadIsPlated if you want to block yourself from placing them.

[Pseudobyte]

They said "core" which to me implies double sided. But yeah absolutely if you want to save on cost you keep all your parts SMT and keep your layer count to 1 or 2. In that arrangement they build a traditional albeit very thin 2 layer board and then laminate it to the Aluminum or Copper before they do the routing operation.

[tszaboo]

They said "core" which to me implies double sided. But yeah absolutely if you want to save on cost you keep all your parts SMT and keep your layer count to 1 or 2. In that arrangement they build a traditional albeit very thin 2 layer board and then laminate it to the Aluminum or Copper before they do the routing operation.

I really just want a one sided panel.

I am using AD19, so maybe you have more options under Tools -> Material Library in a newer version.  You can add custom core and prepreg definitions, but they assume standard materials.  Or maybe newer versions have something under Tools -> Features where I have options for Printed Electronics and Rigid/Flex, but no IMS.

I think this is the answer. I've never seen this menu. Although for some reason the Add menu is completely broken, not showing the names of the fields, I've added ALU 5052 in the "constructions" menu and 0% in the "resin". And then add a layer of prepreg as dielectric layer on top of this.
I still cannot force Altium to do single sided. I remember I already opened a support ticket about that a year ago, I don't think single sided is actually possible in the current version.

They said "core" which to me implies double sided. But yeah absolutely if you want to save on cost you keep all your parts SMT and keep your layer count to 1 or 2. In that arrangement they build a traditional albeit very thin 2 layer board and then laminate it to the Aluminum or Copper before they do the routing operation.

This is a brochure is showing a different construction method, but I've seen the one you are mentioning.
https://www.eurocircuits.com/wp-content/uploads/Poly_A3_4pager_ENG_3_2011.pdf

[Kean]

Another option, though I am not quite sure it is wise...

Define a custom Foil material for "ALU 5052" at 59mil thick, 42oz (or whatever) and set the bottom layer material to that.
As before, turn off layer symmetry to be able to delete bottom solder mask & overlay.
If you need 2 layers, you can add the extra copper and thermal prepreg in between.
Then set up any special design rules you want for clearance, etc.

Of course when I tried that I got the dreaded & never ending "Catatrophic failure" exception and had to terminal the process.

[tszaboo]

Haha, I've speak too soon. The Material library window is completely broken. After adding the Alu core, or anything really, the "OK" in the dialog window stays greyed out. You close the window, all your additions are gone.

Of course when I tried that I got the dreaded & never ending "Catatrophic failure" exception and had to terminal the process.

Please wait a moment ... "Catatrophic failure"
I think it was Altium running out of the 3GB memory if you had many things open, or it was open for a long time, or you worked on a big project.
That is something they fixed in the meantime, it occurs much less.

[tszaboo]

If I try to edit an existing definition, the OK is not greyed out anymore, but it gives me an error message while trying to save, saying I don't have rights to save. What an actual shitshow this is. My question is still sitting at Altium support, they escalated it after asking for screenshots, that was 2 days ago, no reply.
By the looks of it, at some point they had the idea to have an online database of stackups. Then the structure of their server was changed, so when you try to search a stackup online, it forwards you the "Manufacturer part search" window.

[Kean]

Please wait a moment ... "Catatrophic failure"
I think it was Altium running out of the 3GB memory if you had many things open, or it was open for a long time, or you worked on a big project.
That is something they fixed in the meantime, it occurs much less.

Nope, a newly opened Altium session and a single empty PCB to play with.
As you say, Material library window is completely broken!