What is checking fixture datum?
What is checking fixture datum?
The datum of the checking fixture, that is, the datum surface or datum hole on the base (plate), which is the basis for aligning the body coordinate system when measuring the part with CMM (it is also when inspecting the checking fixture).
Datum Surface
It is necessary to further point out that the datum surface has use the upper surface of the base plate, use the lower surface of the base plate, the one that "piles up" small steps (raised) on the upper surface, and the one that "digs" small steps on the upper surface (lower surface).
Datum Line
The datum of the line some uses the two ends of the long side of the base plate, and some use two hole centers.
Datum point
The datum of the point (the third coordinate direction) some uses the short side of the base plate, and some uses the main hole center.
