"Jon Elson" wrote in message
...
Bob La Londe wrote:

"Karl Townsend" wrote in message

if you're cooling that 40 K spindle...

Oh, yeah. without some form of coolant it would just be an exercise in
removing aluminum flavored chewing gum from the flutes.
Well, no, actually high speed machining is usually done dry. The
poor application of coolant to a spindle turning that fast leads to
the cutter heating up and then getting a splash of coolant, and that
causes thermal shock to the cutting edge. Better to just let it get
hot and stay hot. But, you take a lighter cut and move the cutter
past the work as fast as you possibly can to avoid heat buildup in
one area. The bulk material and the chips carry away most of the
heat. I read a book about it, the test case was at Boeing, doing
wing spars. They were running a 75 Hp Cincinnatti spindle at
80K RPM with a 1/2" solid carbide end mill! Feedrate was over
100 IPM (I forget the exact number) and they were removing 640
cubic inches of metal per minute. This was run dry.

Jon

Ok, so show me an example of doing that with a .03125 cutter?