Workholding built for a specific part, which locates it on defined datums and clamps it rigidly enough to cut without moving or vibrating. Good fixtures follow the 3-2-1 principle: three points on the main plane, two on the second, one on the third, then clamp against them. Fixturing decides how many operations a part needs, how repeatable it is and how fast it can be loaded.
Part's simple, the fixturing is the hard part, we need it located off the bore and clamped without bending the flange.
Clamp toward the locators, never away from them, and put clamping force where there is support underneath.
Related terms
Soft jaws
Vise or chuck jaws of aluminum or mild steel, machined in place to cradle a specific part.
Work offset
The stored distance from machine zero to the part zero, so a CNC program runs from the right place.
Parallels
Matched pairs of ground steel bars used to raise a part in the vise to a known, level height.
First article
The first good part off a new setup or program, fully inspected before the rest of the run is made.