HEIDENHAIN TNC 320 User Manual page 100

4.4 TAPPING WITH CHIP
BREAKING (Cycle 209,
DIN/ISO: G209)
Cycle run
The TNC machines the thread in several passes until it reaches the
programmed depth. You can define in a parameter whether the tool is
to be retracted completely from the hole for chip breaking.
1 The TNC positions the tool in the tool axis at rapid traverse FMAX
to the programmed set-up clearance above the workpiece surface.
There it carries out an oriented spindle stop.
2 The tool moves to the programmed infeed depth, reverses the
direction of spindle rotation and retracts by a specific distance or
completely for chip breaking, depending on the definition. If you
have defined a factor for increasing the spindle speed, the TNC
retracts from the hole at the corresponding speed
3 It then reverses the direction of spindle rotation again and
advances to the next infeed depth.
4 The TNC repeats this process (2 to 3) until the programmed thread
depth is reached.
5 The tool is then retracted to the set-up clearance. If programmed,
the tool moves to the 2nd set-up clearance at FMAX.
6 The TNC brings the spindle to a stop at the set-up clearance.
100 Fixed Cycles: Tapping / Thread Milling