HEIDENHAIN IK 5294 - Manual (Page 173)

153
6
Tolerancing
Slots
The tolerance entry screens for slots are used to specify
the acceptable deviation from nominal position, and
from the nominal slot size in length and width. The true
position tolerance compares the measured location of
the center point of the slot to the nominal center point
and compares the measured size to the nominal size.
Enter the acceptable position deviation value, nominal
Length and nominal Width values into the data fields
provided and then click OK.
MMC/LMC (Material condition)
MMC and LMC tolerances are be applied to bosses or to
bores, compare measured center locations to the nominal centers and compare measured radii to nominal
radii. MMC and LMC tolerances can be applied with or without Reference (datum) features. MMC and
LMC tolerances can be applied to arcs and circles.
MMC Arcs and Circles
The MMC tolerance entry screens for arcs and circles are identi-
cal, and are used to specify the maximum material that can exist
within a bore or on the surface of a boss.
MMC tolerances can 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 ac-
ceptable location is given more flexibility. However,
if a bore is exactly the MMC size, no position bonus
is generated and the bore must be located exactly as
specified. When a Reference feature is used and found
to have a tolerance surplus, it also generates a position
tolerance bonus for the bore.
Select the feature type as a Boss or a Bore, enter the
acceptable position Tol Zone value, enter the nominal
radius value, select a Reference feature if required and
then click OK. Reference features of MMC are dis-
cussed in Appendix C: Tolerances.
Maximum material within
a bore
Maximum
material on a
boss
Tolerance Types
6 Tolerancing OE.indd 9 5/9/2005 9:51:51 AM