HEIDENHAIN NC 124 - Manual (Page 82)

7 Drilling, Milling Cycles and Hole Patterns in Programs
82 TNC 124
TAPPING
With Cycle 2.0 TAPPING you can cut right-hand and left-hand
threads.
No effect of the override controls during tapping
When Cycle 2.0 TAPPING is being run, the knobs for spindle
speed override control and feed rate override control are disabled.
Required floating tap holder
A floating tap holder is required for executing Cycle 2.0 TAPPING.
The floating tap holder compensates the tolerances for the pro-
grammed feed rate F and the programmed spindle speed S.
Tapping right-hand and left-hand threads
Right-hand thread: Spindle ON with miscellaneous function M 3
Left-hand thread: Spindle ON with miscellaneous function M 4
Process
The tapping cycle is illustrated in Fig. 7.4 and Fig. 7.5.
I
:
The TNC pre-positions the tool at setup clearance above the
workpiece surface.
II
:
The tool drills to the end of thread at the feed rate F.
III
:
When the tool reaches the end of thread, the direction of spindle
rotation is reversed. After the programmed dwell time the tool is re-
tracted to clearance height.
IV
:
Above the workpiece, the direction of spindle rotation is reversed
once again.
Calculating the feed rate F
Formula for calculation: F = S • p in [mm/min], where
S: Spindle speed in [rpm]
p: Pitch in [mm]
Input data for Cycle 2.0 TAPPING
• Clearance height - HEIGHT
Position in the tool axis at which the TNC can move the tool in
the working plane without damaging the workpiece.
• Setup clearance - DIST
The TNC advances the tool from clearance height to setup
clearance at rapid traverse.
Standard value: DIST = 4 • thread pitch p
• Workpiece surface - SURF
Absolute coordinate of the workpiece surface
• Thread length - DEPTH
Distance between workpiece surface and end of thread.
• Dwell time - DWELL in [s]
A dwell time prevents wedging of the tool when retracted.
Further information is available from the machine manufacturer.
Standard value: DWELL = 0 to 0.5 s
• Feed rate - F in [mm/min]
Traversing speed of the tool during tapping
III IV
A
A
I
B
II
B
A
Drilling Cycles in Programs
Fig. 7.4: Steps I and II in Cycle
2.0 TAPPING
Fig. 7.5: Steps III and IV in Cycle
2.0 TAPPING
A
B
A
B