Quote:
Originally Posted by scottandme
Anything with Al in the coating will not work to cut aluminum. Mainly for chromoly steels, stainless, titanium, nickel alloys, etc. They need high temperatures to "activate", which requires high SFPM numbers. From what I understand it actually creates a thin film of aluminum oxide when it hits that activation temperature. That's purely dependent on the size of the cutter and the material - but 18 to 22k is pretty extreme for a VMC - that's a specialized machine. Most are in the 8k to 12k range give or take. Generally with those cutters they don't use coolant (same with many carbide/ceramic insert cutters), just a heavy air blast to clear chips. The coolant can cause the insert to fracture from thermal shock.
For aluminum you either want uncoated, ZrN, or TiB2. TiCN can work well, but avoid TiN. Most major brands make geometry specifically for cutting aluminum (higher helix, polished flutes, etc, etc).
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So you are basing this on the VMC (Vertical Milling Center) not being able to obtain those high spindle speeds in general?
What if they are using a standard shop router(19kRPM - 25kRPM) or a RotoZip (15k-30kRPM) for a spindle on a homemade gantry?
Course the price they pay is not just for the coating it's also that they will need a high feed rate.
A high feed rate most smaller steppers would have difficulty achieving.
I agree with you if you slow down the spindle and operate more in the range of 8k-12k TiAlN is the wrong coating to use.
Without knowing what sort of machines each team is trying to use it gets a bit more involved.