unusual stackup

No problem doing up to 8 layers with WellPCB. They support up to 12 or so, but 8 is the most I've done.

The stackup will be a little different. They use 0.5 oz Cu on the top and bottom and 1-oz on the inside layers by default.

-- john, KE5FX

sure about that? normally all layers start as 0.5oz and then the outer layers end up at 1 oz during plating of the vias

Yes it sounds as expensive as an 10 layer 1oz layup. In volume the cost comes down to total copper weight. Thermally it doesn't have any advantage. Better make sure it Cu balanced.

That's correct, they plate to 1 oz externally, as I understand it. But their stackup diagram specifies 0.5 oz as it's applied prior to additional plating. Seems like the most common default practice among different Chinese PCB houses.

-- john, KE5FX

Should be fine , the only thing is maybe they would round to the nearest proper thickness based on availble prepreg thickness's. To some +-%. Which would meet your requirements.

Cheers

Doesn't sound goofy. I have done 4oz copper.

sure, but the thick copper is usually on the outside layers done by plating together with the vias

Usually yes but sometimes it's needed inside for high current traces.

Cirexx says it's reasonable and standard material.

It's going to be heavy.

tirsdag den 14. juni 2022 kl. 00.42.50 UTC+2 skrev John Larkin:

That's crazy. Beautiful but crazy.

tirsdag den 14. juni 2022 kl. 01.48.36 UTC+2 skrev John Larkin:

from the comments: "the side that you're looking at has -450V / 0 / +450V traces. The other side has 14V @ 150A and 24V @ 80A."

There are printed circuit houses that specialise in printed transformer windings. The copper needs to end up thicker than pre-pregs it gets printed onto.

Specialised stuff, but there seems to be quite a bit of it about, looking at the transformer cords designed to accomodate them.