Here is what I have gathered so far, in case it helps anyone: 1) print ABS enclosed in a chamber temp of a minimum 50C, ideal 60-80C. 2) use quality filament, Polymaker filament is good; issues are plastic composition and diameter variation. 3) dry the filament properly. 4) the fumes will destroy your lungs and eventually the printers themselves, so they need to be vented out, and also filtered inside the enclosure. 5) bed flatness is critical. 6) use a good bed adhesive such as Magigoo.
https://www.reddit.com/r/3Dprinting/comments/7n0go2/my_first... for an anecdote.
I am also in a bit of an unusual situation because of the size of the parts: voluminous enough that shipping from the manufacturer is no longer negligible.
Oh, and unfortunately can't do resin because of strength reasons. 3D printed ABS is already pushing it.
Or you pay a lot of money for a higher end printer and make use of a support contract where they can figure out where your parts are failing.
One other suggestion would be to contract the parts out to a company like Shapeways and see if people are actually able to reliably make them in low volume, then try to replicate. May be a dumb question, but presumably you've tried to print the same parts in PLA or a more forgiving material to confirm that they are "printable"?