first,choose your tool to cut.Only a carbide- or diamond-tipped cutter has the tensile strength to mill carbon graphite without fracturing. second,Selecting Spindle Speeds. Choose high-spindle speeds when milling carbon graphite. Cutting carbon graphite material generates low temperatures because the CNC tools actually chip small amounts of the grahpite carbon away from the milled part. Higher spindle speeds provide the best environment to cleanly chip,or mill, the carbon materials without chipping or shattering the piece. third,Selecting Feed Rates When milling carbon graphite,choose slow material-feed rates. The carbon material easily fractures if the feed rates are too fast. When drilling completely through carbon graphite material,higher success is achieved by drilling halfway through the middle part from each direction. This strategy prevents the graphite from chipping as the cutting tool exits are graphite material. The high-density properties of the carbon graphite are also likely to snap off the cutting tool if fed through the equipment to quickly. hope it helps!