Micro-EDM-milling uses basically the same ideas but for much smaller electrodes (diameter smaller than 0.8
mm). At this size the electrodes are flexible and it is not
obvious to use them as accurate milling tools. Therefore,
this situation had never been studied. To solve this
difficulty, micro-EDM-milling use a dynamic effect of
rotating at high speed the electrode to rigidify and strait
it. The sparks occur at the tip of this tool, so to remove
the material without cutting forces. This fact is of great
interest as it allows to machine deep cavities with high
accuracy without any risk of tool break. The wear of the
electrode is compensated by a programmed declining
trajectory.
All this makes the machining conditions quite
unconventional (typical hydrodynamic, sparking plasma
in dielectric with velocity gradient, mechanical stability
of flexible rotating electrode). So the physical basis of
this process has to be investigated in order to prove the
industrial feasibility of this innovative technology. The
main results of this research are here presented.