I am reworking a module for the JLCPCB aluminium core board and am wondering how to set this up in the stackup?
I have one copper layer “F”, a 0.1mm dielectric and a 1.5mm aluminium plate.
No “B” copper
The generic term for this is IMS, (Insulated Metal Substrate). In it’s simplest form these PCB’s do indeed have only one copper layer, and no via’s, but there are variants with more copper layers. And apart from the single layer, and no via’s nor THT parts I guess there is not much special for settings inside KiCad. But you could do a bit of searching to find more hints.
1 Like
Experimenting with the stackup editor and directly editing the text PCB file, it looks like KiCad just does not directly support any asymmetrical board structure. A pity as these IMF boards are now becoming far more common.
I can create usable Gerber plots, but no realistic 3D rendering or STEP model
Just recently, I read a post about someone using KiCad for designing something on a ceramic substrate, which is apparently built up with one layer at a time and can extend upto 50 or so layers. Maybe it’s time to create a future request for such “less common” layer stackups, but I don’t know much about them, and I’m not the right person to formulate such a request.
Done
These boards are getting common, LED arrays etc
2 Likes
This has been closed as a duplicate of Allow an odd layer number / asymmetric stackups (lp:#1829379) (#2425) · Issues · KiCad / KiCad Source Code / kicad · GitLab
I disagree with this as the original issue was really about creating a single sided FR4 PCB, where simply ignoring the B layer is a working solution.
The fundamental issue is asymmetry and two non copper layers touching
1 Like
No, we are using the original issue to track the need to support asymmetrical stackups.
I know 3D printed boards have limitations right now, but is the idea of stack up kinda out the window if these get more mainstream?
Without a Sketch of the Cross-Section, I don’t fully understand what the goal (the Image) would look like (my own brain limitation).
That said, you can set the B-Cu thickness to Zero and achieve some Asymmetry
1 Like
You need to be able to specify multiple different non-copper layers adjacent to each other to do it properly. In the case of IMS, you need a dielectric next to a metal (not copper) layer.
For now, the solution is to just specify the stackup in a technical drawing. This works fine, you just can’t define the details inside KiCad’s stackup editor or see them in the 3D view.
and you have to exert mental pressure to refrain from using via’s or the non-existing copper layer in the PCB. You probably can write some custom rules that flag any THT pads, via’s or copper on the other side.
Concerning this tracking… is it a good idea to mention IMS and LTCC in that other / older thread too?
using via’s or the non-existing copper layer in the PCB
Place one giant rectangular rule area (disallow vias) across the whole board.
2 Likes