Black Slate Engraving

[phill05]

Yes it is possible to cut slate with carbide but the cutting edge has to be ground to a different angle to give a small back relief to preserve the cutting edge, in reality you are grinding the stone not cutting it, If you want 1mm deep you would do this in 1 pass.

Your cnc machine also needs to be very rugged with water flood.

The image below shows a 2.5d relief that is 8mm high for the flower and 6mm high for the text all the stone between is ground out with 2mm roughing passes then change to a V cutter to do the relief in 2mm passes.
as regards feeds you need to test cut on each type of stone, on old stone that has oxidised/hardened you will find it is slow.

Phill