HEIDENHAIN ND 1300 OED and Crosshair Systems - Manual (Page 151)

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7
Tolerancing
MMC/LMC (Material condition)
MMC and LMC tolerances can be applied to bosses or to bores, compare measured center locations to the
nominal centers and compare measured diameters to nominal diameters. MMC and LMC tolerances can
be applied to circles and arcs.
MMC Circles and arcs
The MMC tolerance screens for circles and arcs are
identical, and are used to specify the maximum mate-
rial that can exist within a bore or on the surface of a
boss.
MMC tolerances generate position bonuses as a result
of size tolerance surpluses. For example, when the size
of a bore is larger than MMC, but within the acceptable
tolerance range, a position tolerance bonus is generated for the bore and its acceptable location is given
more flexibility. However, if a bore is within the position tolerance diameter, no position bonus is gener-
ated and the bore must be located exactly as specified.
Touch the Boss or Bore choice
field to specify the feature type as
a Boss or a Bore.
Enter the nominal values into
the X and Y axis and D (diam-
eter) data fields provided. Enter
the allowed Tol Dia (Tolerance
diameter) and feature diameter
limits into the Limit data fields as
+/- ranges or as absolute limits.
Touch the Limit data fields to
toggle between +/- ranges or ab-
solute limits.
Maximum material within
a bore
Maximum material on
a boss
Tolerance Types