HEIDENHAIN TNC 426, User Manual

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234 8 Programming: Cycles
8.3 Cy
cles f
o
r Dr
illing, T
a
pping and Thr
ead Milling
U Set-up clearance Q200 (incremental value): Distance
between tool tip (at starting position) and workpiece
surface
U Thread depth Q201 (incremental value): Distance
between workpiece surface and end of thread
U Pitch Q239
Pitch of the thread. The algebraic sign differentiates
between right-hand and left-hand threads:
+ = right-hand thread
– = left-hand thread
U Workpiece surface coordinate Q203 (absolute
value): Coordinate of the workpiece surface
U 2nd set-up clearance Q204 (incremental value):
Coordinate in the tool axis at which no collision
between tool and workpiece (clamping devices) can
occur.
U Infeed depth for chip breaking Q257 (incremental
value): Depth at which TNC carries out chip breaking
U Retraction rate for chip breaking Q256: The TNC
multiplies the pitch Q239 by the programmed value
and retracts the tool by the calculated value during
chip breaking. If you enter Q256 = 0, the TNC retracts
the tool completely from the hole (to set-up
clearance) for chip release.
U Angle for spindle orientation Q336 (absolute
value): Angle at which the TNC positions the tool
before machining the thread. This allows you to
regroove the thread, if required.
Retracting after a program interruption
If you interrupt program run during thread cutting with the machine
stop button, the TNC will display the soft key MANUAL OPERATION.
If you press the MANUAL OPERATION key, you can retract the tool
under program control. Simply press the positive axis direction button
of the active tool axis.
Example: NC blocks
26 CYCL DEF 209 TAPPING W/ CHIP BRKG
Q200=2 ;SET-UP CLEARANCE
Q201=-20 ;DEPTH
Q239=+1 ;THREAD PITCH
Q203=+25 ;SURFACE COORDINATE
Q204=50 ;2ND SET-UP CLEARANCE
Q257=5 ;DEPTH FOR CHIP BRKNG
Q256=+25 ;DIST FOR CHIP BRKNG
Q336=50 ;ANGLE OF SPINDLE