I’m laying out a PCB with ampere load currents, millivolt sense voltages, and PWM drive, all connected to an Arduino’s strictly digital ground layout through the usual headers. While I’ve laid the board out with the high-current stuff over there, the sense inputs here, and the PWM as far off in its own corner as possible, I fear this will get ugly.
One step to reducing the noise involves a decent ground system. The Arduino pretty much eliminates the whole single-point ground concept, so I’m using a double-sided ground plane with plenty of Z-wire stitching , plus copper tape around the edge binding the top and bottom planes.
The PCB is 60 mils thick, so I cut four copper foil strips about 3/16-inch wide, folded them around the board edges, then burnished the surfaces flat.
Although the tape has adhesive on one side which is allegedly conductive, I figured running a solder bead along the edges couldn’t possibly hurt. That worked out reasonably well, if you don’t mind blobular solder along the edge of your board.
The joint along the bottom edge shows one problem: some adhesive oozed out while soldering and formed a barrier. I think that happened along the tape edges from the outside of the roll, because it’s most prominent along two board edges.
Memo to Self: Slice off and discard the outer few millimeters. Mask the outer board edge for a solid pour, not a hatch.
The Smell of Molten Projects in the Morning 
Comments
4 responses to “Copper Tape for PCB Edge Binding”
Out of curiosity: why do you hatch the main body of the board, rather than do a solid pour everywhere?
It’s a quick-and-dirty check that I’ve actually etched evenly across the whole board: as long as any of the little squares remain bright & shiny, I keep etching. Otherwise, I must scrutinate all the traces and, inevitably, I miss a couple.
Plus: it’s photogenic. That counts for much more than you’d think…
Plus, less need for thermal vias for your Z-wires and other ground connections; if you’ve never tried to solder a tiny wire to a 2oz solid ground plane, let me assure you it is all kinds of No Fun even with a *good* station.
And hey, it saves weight! :)
One of our recent boards ran 40 amps to an LED, so we ended up putting polarpaks and llps, both packages with only bottom leads, on a 12 ounce copper board. Hotplates are fabulous for thick copper shenanigans.
Photogenic is good, and etch-gauging is excellent. Now to see if gEDA can do hatches. I’d probably just have to draw tracks, but that’s okay.