Re: [CAD_CAM_EDM_DRO] Milling titanium

Tom Murray wrote:

> Is it possible to mill titanium on a benchtop mill (i.e. Sherline,
> Taig, or MaxNC)? If so, what is the ideal speed of travel, spindle
> speed, and type of cutter.

The surface speed of the cutter is determined by cutter and workpiece
material. But, I can't give you a speed in RPM, as that depends on tool
diameter. For HSS cutters on Titanium, surface speeds range from
100-125 SFPM for pure titanium to 25-45 SFPM for 6al-6v-2sn
alloy. You figure RPM = SFPM/(Pi * D/12). For 50 SFPM with a .25"
diameter cutter, that comes out to 763 RPM. Feed is best determined
by surface finish, rigidity of machine, width of cut, etc. on your own
machine. Very generally, with HSS tools, a chip per tooth of
.005"/cutter diameter is a good starting place. For a 4 flute cutter
at 750 RPM, that would be .005"*.25 * RPM = .9375 IPM, so 1 IPM
would be a good guess.

Solid carbide can take about 2 x the surface speed on titanium, the other
parameters are about the same. You can remove from .7 down to .3
cu In per minute per spindle horsepower, depending on the toughness
of the titanium.

> Is coolant required?

For HSS it is absolutely necessary, for carbide it may or may not help.
The coolant can thermally shock the cutting edges. causing cracking.
If that is not a problem, then it should help.

Jon