Re: [CAD_CAM_EDM_DRO] Re: shielding for steppers

In a message dated 22-Nov-01 12:13:11 Central Standard Time, cncnut@...
writes:

> Will wrapping the wires with alluminium foils be sufficient for
> shielding?

Peter: For "still" cables, this would be "electrically OK", so long as you
"GROUNDED" this foil-wrap. You could do this reasonably-effectively by
wrapping a dozen spiral turns of #18 tinned copper wire over the foil (alum.
does NOT make a good "contact material"!), and then ELECTRICALLY connect the
end of that copper wire to "machine ground" in a proper fashion.

If you must do this over a "flexible link", say, where a motor is part of a
moving carriage, you might do it "electrically best" if you nicely wrap a
"ribbon" of alum. foil in ONE direction, then lay bare stranded #18 tinned
copper wires along this foil (two should do, opposite sides, but CONTACTING
the aluminum, all-along!), and then wrap the spiral-copper-wire over the
link, maintaining a "neat" spacing about 1/4" between turns. Then,
"double-wrap" at the ends, and bring the END out, to that proper "electrical
connection" to machine-ground.

Lotta hassle, but it may be MORE hassle to remove the wires, slip braided
shield over that, solder a "pigtail" on the end, then slip shrink-tubing over
all that, and shrink, etc. and then solder the wires back, again! Put a
"company-logo" on that shrink-tubing! Summin to THINK on...

Jan Rowland, Troll


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