A few nice 3d China milling images I found:
Small 3D mill machine
Image by by Marc Huguet Reyes
3D mill machine cooper layered board.
Especially useful for electronic circuit board digital fabrication.
3D China Milling with a CNC Router
Image by AS220
Jens Dyvik taught members of AS220 Labs how to use the CNC Router to do 3D China Milling.