[TheForge] Not entirely OT - just neat CNC video

[Andrew Vida]

About twenty years ago I was reading an article in Mechanical 
Engineering on s a flight to a client that described a process called 
"whirling" - a machining method by which unorthodox tool paths utilizing 
high surface speeds, heavy cuts,and special tooling materials and 
geometries are used such that better than 99% of the heat generated 
remains IN THE CHIP.

The result of this augmented tool path philosophy is faster machining, 
virtually no heat transmitted to the machined part, and vastly improved 
cutting tool life.  The article quoted a manufacturer of ring and pinion 
gears for automotive final drives which stated that tool life for 
cutting fully hardened gear blanks went from 13K to about 230K before 
needing to swap tools, as I recall but do not quote me on those figures. 
  The point is that tool life grows dramatically when tool paths are 
more precisely calculated for a given geometry of cut, material, heat 
treat, etc.  These precisely determined tool paths, coupled with the 
right cutting tool geometries and materials such as CBN and diamond, 
confine heat to the chip almost entirely.

This is a short video by Becker, a German manufacturer of such tooling. 
  It is a demonstration of machining high-hardness materials at very 
high speeds - the threading is particularly impressive, as is the fact 
that they held tolerances of 0.95 MICRON on such materials with 
beautiful surface finishes.  They guarantee consistent 3 micron 
tolerance in materials as hard as RC60, which is quite impressive.  You 
will immediately note how most of the chips coming off the work glow 
bright yellow as they shear away.  Good fun, this.

http://www.youtube.com/watch?v=bvHMVkfweCc