HEIDENHAIN ND 1400 - Manual (Page 91)

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7
Tolerancing
Position/MMC and LMC (Material conditions)
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, arcs and cylinders.
MMC Circles, arcs and cylinders
The MMC tolerance screens for circles, arcs and cylin-
ders are identical, and are used to specify the maximum
material 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, Y and Z axis and D (diameter)
data fields provided. Enter the al-
lowed Tol Dia (Tolerance diam-
eter) and feature diameter limits
into the Limit data fields as +/-
ranges or as absolute limits.
Touch the Limit data fields to tog-
gle between +/- ranges or absolute
limits.
Maximum material within
a bore
Maximum material on
a boss
Tolerance Types