Say you do the "4 Corner" or Appearance Process Window and all the visually parts are "good" dimensionally, giving a Cpk in excess of 2. Would doing a "DOE" be necessary?
I have a couple of molds that we are validating that are so tight, we can't get them to flash, even after more than doubling the pack pressures required to produce a visually good part.
The customer also gave us super-wide tolerances.
KOM
brent