The segment is heat-treated to relieve machining stresses
, and then the mirror side is roughed before another stress-relief treatment.
Finally, he rests the part for 24 hours to resolve any induced machining stresses
, then finish-bores the larger diameter to the required +/- 0.0006" tolerance on a Mazak.
Unlike annealed stampings, fully hardened electroforms need no heat-treating and have no induced machining stresses
that can distort finished shapes.
Features include a single-piece solid steel base designed to resist machining stresses
during high-speed routing.
Potentially far more expensive, a broken parting tool could inject unwanted carbide and machining stresses
into a critical aerospace component worth several thousand dollars.
When the thread is large, such as 4 to 6 pitch or 4 to 6 threads per inch, conventional tapping tools won't stand up to the machining stresses
and won't make a straight hole anywhere near as deep as required.