Don,
Does your machine have a nosecone depth regulator?
What they do, is ride on the surface of the material and allow the tip of the cutter to protrude, to a predetermined depth.
Without a depth regulator, you'll have a tough time achieving a consistent-looking character.
The speed (RPM) of your motor won't be as crucial a factor as the speed at which you have the cutter work through the material, which, for metal, should be fairly slow. You'll know you're moving too fast, if the tip of your cutter snaps off. >.<
Also, keep in mind, that since the nosecone comes in direct contact with the metal, it will scuff the surface of the metal.
No problem if the metal is unfinished. You can lightly sand the plate to render a brushed finish.
If the surface is finished, (polished, lacquered) you can apply a thin piece (.025) of plastic engraving stock, over the engraving area, with an adhesive spray, which will allow you to engrave through that top layer, while protecting the copper plate. David "The Stunt Engraver" Lavaneri
DGL Engraving
Port Hueneme, CA |