HEIDENHAIN TNC 320 (340 551-01) - Manual (Page 204)

204 8 Programming: Cycles
8.2 Cy
cles f
o
r Dr
illing,
T
apping and Thr
ead Milling
Danger of collision!
Always program the same algebraic sign for the infeeds:
Cycles comprise several sequences of operation that are
independent of each other. The order of precedence
according to which the work direction is determined is
described with the individual cycles. For example, if you
only want to repeat the countersinking process of a cycle,
enter 0 for the thread depth. The work direction will then
be determined from the countersinking depth.
Procedure in case of a tool break
If a tool break occurs during thread cutting, stop the
program run, change to the Positioning with MDI
operating mode and move the tool in a linear path to the
hole center. You can then retract the tool in the infeed axis
and replace it.
The TNC references the programmed feed rate during
thread milling to the tool cutting edge. Since the TNC,
however, always displays the feed rate relative to the path
of the tool tip, the displayed value does not match the
programmed value.
The machining direction of the thread changes if you
execute a thread milling cycle in connection with Cycle 8
MIRRORING in only one axis.