I’d hate to be a traction motor driver layout guy… The 4oz copper is not compatible with fine pitch SMT etching.
I have solved it in the past with using a sandwich of 1 oz 2 layer sandwiched to a 4oz 2 layer to create a hybrid 1oz / 4oz board and it wasnt great.
During reflow is where the problems start due to warp . Not warp like warp field. Warp due to different copper weights generating different expansions . The bottom 1oz side had to have copper poured up to an inch of its life, and there needed to be copper pour cutouts on the thick side to control the expansion.
How much current goes though those wires?
How many PCB’s are you planning to make?
Another option is to use “bus bars”
Those bus bars come in many forms. I think there are some standard sizes you can buy off the shelf, but often these are custom products made to size. There are also variants made from a piece of copper wire and connectors you can screw on any location on the wire.
You should consider designing the PCB using bus bars that can carry hundreds of amperes.
An example of such a design is the kWeld spot-welder that will supply in excess of 1000A (peak).
I tried to solder wires to one commerical/third party pcb board on traces instead of trying to get multiple wires directly connected on to 0.4mm pitch chip legs and failed miserably.
I used the sharp knife and fiberglass brush to remove the solder mask and I got the copper visible. And then I cleaned it multiple time with the 91% isopryhol alcohol. (Needed to do multiple times, as it seemed that on first times the alcohol actually spread the solder mask from surrounding areas back to exposed copper)
After that applied solder paste before trying to solder the wire to it and I just could not get the solder tin to attach to the board, it just stayed on my solder iron.
In some youtube videos it looked so easy, but not for me in real life. Do you have any extra ideas how to do this properly?
Once you get the Track/Copper cleaned (very clean!) you can coat it with Tin. You can buy it online or, make your own. Here’s my link on making it (and, Click the ‘more’ and read the Comment someone posted at the original posted ‘Short video’ - he was a happy camper when done…)
You won’t want to submerge a completed PCB but, perhaps you can ‘Brush, Swab’ it on multiple times as it needs at least one minute to plate the copper…
