If you ran those parts wet, the endmill probably wouldn't have lasted the whole video... Carbide can take a lot of HEAT a LOT,
get it as hot as you want, and it really doesn't care.. What carbide can not take very well is rapid heat cycling... HOT COLD HOT COLD
thousands of times a minute, KABOOM, bye-bye endmill...
The temperatures involved are not tiny... That dark purple coating AlTiN or TiAlN, that purple stuff doesn't start working its magic
until about 1700 degrees F. Then it gets really hard, and really slippery. That coating is essentially taking the place of the slippery
stuff in your coolant.. Chlorinated parafins in most coolants (which start working their magic at around 700 degrees) or sulfur in an
old school cutting oil (about 900 degrees).
Oddly, even in aluminum I've found... Get those speeds way up, and you can generate enough heat, and heat cycling to chip out
carbide.
On the lathe even... Interrupted cut.. Say turning some hex.. I'll run it dry until I get it round, then bring the coolant in once
I'm in a constant, non-interrupted cut.
Running dry is nothing more than another tool to add to your tool box. The first couple of times you do it, it just seems wrong... It
seems REALLY wrong doing it in aluminum.. Its just another tool, some things just work better/run faster when dry.
Here is some 6061 running dry that I did, old beat up Fadal, pretty close to topping out on the feedrate.. I recently ran 140 of those,
but an inch deeper and an inch longer... Never even had to rotate the inserts... The programming is not efficient, but at that point
I had already saved so much time as opposed to going at it conventionally, I didn't care. I've run those speeds wet, and the inserts
chip out, dry, they literally last forever.
