HEIDENHAIN iTNC 530 (340 422) ISO programming User Manual
Page 259

HEIDENHAIN iTNC 530
259
8.3 Cy
cles f
o
r Dr
illing
, T
a
p
p
ing
and
Th
read Millin
g
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.
