Machining some heat resistant stainless castings. Dont know the true properties of the metal other than HARD. This is work that i can probably keep coming back every month if i can get the cost down enough to be competitive on pricing. The parts are large tubes about 6" in diameter with the ends machined into a weld bevel. Right now i am using a carbide inserted 2 flute 3/4" ball mill to contour the bevels to shape. I am running at 690SFM with a chipload of .014". Any faster and the inserts get over heated and degrade to fast. Also running dry as any coolant thermal shocks the inserts immediately.

So my question is just how much more SFM could i expect to get from a solid carbide 4 flute ball mill with Tialn coating? And at $20 per insert for the cutter im using now i can get 2 completed parts before needing to change the insert. At $260 for a solid carbide tialn coated mill i would have to get 20 parts per end mill to end up with the same cost per part for tooling running the same SFM and feedrate. However if i can achieve an increase of x4 in cutting feed i only need to get 4 parts per end mill to significantly increase my profit margin.

Is this pie in the sky or is that a reasonable expectation for switching to tialn carbide? I have never tried tialn coated carbide yet. We usually go for the cheap and slow method but its time to get caught up with the rest of the world in milling speed if we are to stay competitive.