My customer desires to secure #0 or #1 gage stranded copper wire to a PCB.
Other than striping the insulation, it is desirable that no other
preparation of the wire is permitted. Is there some kind of approved
transitional component that can be securely fastened to the PC board,
provide a good interface to the copper pour on both sides and be capable of
handling such heavy wire?
I would certainly use .090" PCB construct form factor to start.
Two methods. The industry standard is to crimp a lug on the cable
end and either solder the flat lug to the PCB or clamp it through a
plated hole with a copper stud/screw/nut. The wire then need a huge
strain relief clamp directly after the connection within the first few
inches of the board. That way both the PCB and the connection never
sees any mechanical stress. If the cable has to be free all the way
up to the board, you are asking for a failure mode.
To do it with no crimped lug, I would still us .090", and place a
good 2,25 sq inch (1.5x1.5) unmasked area on the board with a series
(array) of at least .200" plated holes in the area. Un furl the cable
strands, and make a series of "dredlocks" to place into the holes.
For vertical, perpendicular entry, you fan out the dredlocks, fit them
through the holes, and commence solder operations after using liberal
amounts of externally applied flux. For a horizontal, co-planer (as
it were) entry method, the same dred locks can be used, but would need
to be longer. In BOTH cases stantioning/fixturing of a cable that
large is required
You need a huge iron and tip for this, and I would recommend s good
ACTIVE flux, and the cable must be new copper.
A third way would be to maybe make a small 0.090" inch PCB not much
bigger than the cable diameter... say 0.250 or 0.375 apron bigger that
you would fit onto the end of the cable, and then mate it to a hole in
a 0.090" "main board" that is the rest of your layout. The cable end
PCB would then get SMD mounted to the main PCB.
All cases require very good fixturing on both the PCB and cable as a
single immobile pair respective to each other. A cable that big may
not break free from the pcb, but it may well tear up the PCB
surrounding elements through flexure. That's why I suggested the
0.090" material.
You can strengthen the board by adding layers inside too, but then
cost goes up.
A fourth way would be to solder the dread locks onto some 0.040" or
0.050" (or more!) copper sheet square or round cut with holes drilled
in it, and SMD that onto the PCB. You could even give it rows of
perimeter teeth that way
That would be:
Holey slab-o-copper with toothy apron, 0.2 inches bigger than the wire
dia. with 0.200 long teeth which get bent down 90 degrees all around
(square is easier but round is doable).
A PCB with your circuit or feeds to it, and a square plated hole
pattern to match the teeth (like 24 teeth a couple mm wide each) and a
big through hole in the middle to clear the big wire array.
The solder flow makes perfect standard through hole solder joints on
all the teeth, and a nice SMD fill on the part of the copper plate
that overlaps the PCB on th top side, VERY strong method, but a
custom part. But hey, so is the PCB!
The apron on the PCB which accepts the SMD fillet(s), the through
holes, and even an extended area can be fitted with an array of plated
VIAs that allow for better thermal handling, and likely add some
strength and ampacity.
You could make a strain relief in the form of a bunch of solid copper
(tinned of course) wires that go from this attachment PCB over to your
main PCB at like a two inch vault. Like 15 or twenty 18 Ga pieces.
Bend a slight S shape in the center of each. That separates your
main board from any flexure problems and makes the whole thing more
serviceable.
Any way one looks at it, such a big cable is not an easy attachment.
Fanning it out into the "dred lock" thing will give it some flexure
capacity too as long as you do not let the solder wick up into them
too far (not easy).
The crimp method is actually far more serviceable, needs no soldering,
and is only one additional part, and a hug crimper away.
All the VME chassis us 0.090" PCB media. They clamp copper bars to
the board, and the tie the wire terminal lugs onto that via studs.
You could do that too. Make the bar/PCB combo fit your rules of
attachment to both sides via the clamping methods used, and either
stud it, or drill and tap it for a bolt and crimp a ring lug on the
wire and viola!
OR you could make the bar/PCB combo, and add a CLAMPING bar to the
top of that, that you fit the wire into. Two tightened bolts later,
and she's clamped!
That one is likely the most serviceable. Make sure to use
antioxidant on that one though.