This is one of a pair of miniature punches and dies that could only be produced with the EDM process.
Both parts are extremely hard toolsteel ; over 60 Rockwell C.
Shown are 2 shots of a micro sized medical part in 17-4 PH stainless steel. The part is micro drilled, wire EDM cut and the cut-off stub is hand finished. The part is tiny: it is 0.050″ (1.25mm) long and 0.030″ (0.75mm) wide. The wall thickness is 0.004″ (0.1mm) at the thick points and the part is accurate to within 0.0003″. It was a challenge to cut this tiny part, mostly because of the difficulty in not losing or destroying it when it was cut off from its stem.
|The part still in the EDM worktank and attached by a tiny stem to the material blank. The 0.015″ start hole for the next part is also visible. The stem is 0.005″ wide|
This is a stainless steel tube that forms part of a needle biopsy instrument. The tubing is very thin…the wall is 0.004″ thick. The slots need square ends and must be precisely oriented around the tube. The slots must be bur-free since other parts slide in the tube. Despite its expense, EDM is the obvious processing choice for a part like this.