HEIDENHAIN ND 1300 OED and Crosshair Systems - Manual (Page 143)

125
7
Tolerancing
Chapter 7:
Tolerancing
Tolerances can easily be applied to position, size, orientation, form, runout and concentricity measure-
ments using the tools found in the tolerance screens.
CAUTION
Discrete point measuring machines estimate the size, position, orientation, and form of
geometric features based on points probed. When parts are designed with critical tol-
erances, be sure that you have probed sufficient points to calculate a reliable estimate.
For example, if you probe a circle with only three points, the circularity will be perfect
and the circle will always pass a form tolerance test.
CAUTION
The QC-300 uses a best fit algorithm to estimate the size, position, orientation and form
of geometric features. While the best fit yields very useful information, the results do
not necessarily reflect how well the parts will fit together and perform their function.
For example, a hole diameter could be calculated as 10.000 mm but have poor form.
In this case, a 9.9 mm pin might not fit in the 10.000 mm hole.
NOTE
Tolerance calculations comply with the ASME Y14.5M-1994 standard except as noted
in the tolerance section of Chapter 12: Reference Materials.