Hi Dave,

Of the 6 parts, 2 are always the same PN. They were sent out together for shot peening (one of the problems: black box, we don't know what our subcontractor is doing and with covid we can't visit them).
We see for example for the same hole on the same PN (but different part):
part 1 : -5µm diameter change because of shot peening
part 2: -16µm diameter change because of shot peening.

The other PN are very similar (minor thickness change of non-holes), and there it's not consistent neither.
With tight tolerances, such big difference after shot peening between parts is difficult, as we don't know how to adapt our machining to take into account the shot peening.