HEIDENHAIN TNC 426 B, User Manual

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139 HEIDENHAIN TNC 426 B, TNC 430
Insert rounding arc between straight lines: M112
For reasons of compatibility, the M112 function is still available.
However, to define the tolerance for fast contour milling, HEIDEN-
HAIN recommends the use of the TOLERANCE cycle (see section
8.8 ”Special Cycles”).
Machining small contour steps: M97
Standard behavior
The TNC inserts a transition arc at outside corners. If the contour
steps are very small, however, the tool would damage the contour.
See figure at upper right.
In such cases the TNC interrupts program run and generates the
error message “Tool radius too large.”
Behavior with M97
The TNC calculates the intersection of the contour elements — as
at inside corners — and moves the tool over this point. See figure
at lower right.
Program M97 in the same block as the outside corner.
Effect
M97 is effective only in the blocks in which it is programmed with
M97.
A corner machined with M97 will not be completely
finished. You may wish to rework the contour with a
smaller tool.
7.4 Miscellaneous F
unctions f
or Cont
our
ing Beha
vior
X
Y
X
Y
S
16
17
15 14
13
S
Large tool radius
Move to contour point 13
Machine small contour step 13 to 14
Move to contour point 15
Machine small contour step 15 to 16
Move to contour point 17
Example NC blocks
5 TOOL DEF L ... R+20
...
13
L X ... Y ... R.. F .. M97
14 L IY–0.5 .... R .. F..
15 L IX+100 ...
16 L IY+0.5 ... R .. F.. M97
17 L X .. Y ...
Hkap7.pm6 30.06.2006, 07:03 139
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