Do "aluminum" and "copper" PCBs really contain a slab of metal? - Page 1
Forum section: electronics / projects

author: incf
author_rank: Frequent Contributor
timestamp: May 25, 2025, 05:29:50 pm
content: On Asian PCB websites they offer "aluminum" and "copper" PCBs. But I find that they sometimes don't make the stackups clear.This prompts a simple question:(1) do these sorts of PCBs really contain a solid sheet of metal?(2) how does V-scoring work on these sort of PCBs?(3) are these PCBs stiffer than FR4?Thanks!

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 25, 2025, 06:35:23 pm
content: Quote from: incf on May 25, 2025, 05:29:50 pmYesQuoteSimilar, though you may need to bend couple of times to seperateQuoteSimilar, but ali. can bend and stay bent to form into shapes. Traces will be OK as long as bend is concave, i.e. compressing, not stretching the copper.

author: incf
author_rank: Frequent Contributor
timestamp: May 25, 2025, 06:59:48 pm
content: Quote from: mikeselectricstuff on May 25, 2025, 06:35:23 pmThat's interesting. Can you speculate about the minimum bend radius before reliability is compromised?I'm wondering if it could be used structurally almost as if it was a piece of sheet metal. (eg. make a box or bracket with traces on it)

author: shabaz
author_rank: Frequent Contributor
timestamp: May 25, 2025, 07:50:08 pm
content: Quote from: incf on May 25, 2025, 06:59:48 pmI have tried that, spacing holes in the alu PCB to make a bend line. You'd have to experiment to find what's most useable though, since it's a compromise between ease of bending, and strength, because the material cracks with sharp bends (i.e., you'll see the surface of the aluminium visibly fractures and noticeably significantly weakens, but, provided you don't try to bend it back, then it is useable (but barely; you'd need to perhaps use epoxy glue to strengthen it back up). That's with 90 degree sharp bends, but a curve could be more useable, or several less sharp bends (but then some of the effort will be to make a suitable jig to form the several bends). Another option could be to use 3D printing to form a chassis and then screw on flat plates.Edit: see attached close-up showing the fractured material on a 90 deg sharp bend that used holes as a guide line.

author: incf
author_rank: Frequent Contributor
timestamp: May 25, 2025, 08:14:53 pm
content: So this mystery metal aluminum core acts like heat treated 6061-T6 when bent: brittle, crumbly.Might have to be annealed to be soft enough to bend.You'd think putting it through a reflow oven might be enough to anneal it. But maybe it's not a long enough duration.I'd imagine that bending it around a 1" (25mm) rod might be more forgiving and maybe preserve the traces.

author: shabaz
author_rank: Frequent Contributor
timestamp: May 25, 2025, 08:27:23 pm
content: I tried very crude annealing (in a not very scientific way, just with a pre-heater and blasting with hot air), but it didn't improve things much for me unfortunately. However, now 3D printing of prototypes is quite low cost, so I end up using a combination of techniques including that, and might revisit alu PCB bending again at a later date.

author: fourfathom
author_rank: Super Contributor
timestamp: May 25, 2025, 09:40:36 pm
content: Quote from: incf on May 25, 2025, 05:29:50 pmI've used the aluminum PCB from JLCPCB, mainly for the heat-spreading characteristics.It is *just* a solid sheet of metal, with copper traces over some very thin dielectric.I don't know about V-scoring.FR4 is stiffer.Note that these PCBs are single-sided and any holes are not insulated from the aluminum core.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: May 26, 2025, 09:36:12 pm
content: The industry naming for this is IMS (= Insulated Metal Substrate). and as other have written here, it's a piece of sheet metal, then a thin layer of paint, and copper conductors on top of that. They are mostly used as a heat sink and heat spreader. They are quite popular for LED lighting.Normally these are single layer boards, but there are some manufacturers that can make these dual layer, and even use via's that do not short to the metal core.

author: thm_w
author_rank: Super Contributor
timestamp: May 26, 2025, 10:02:29 pm
content: The stackup is very clear if you look for it:https://jlcpcb.com/help/article/jlc-aluminum-substrates-are-now-available