HEIDENHAIN TNC 426B (280 472) ISO programming - Manual (Page 178)

8 Programming: Cycles 162
RIGID TAPPING (Cycle G85)
Machine and control must be specially prepared by the
machine tool builder to enable rigid tapping.
The TNC cuts the thread without a floating tap holder in one or
more passes.
Rigid tapping offers the following advantages over tapping with a
floating tap holder
■ Higher machining speeds possible
■ Repeated tapping of the same thread is possible; repetitions are
enabled via spindle orientation to the 0° position during cycle call
(depending on machine parameter 7160).
■ Increased traverse range of the spindle axis due to absence of a
floating tap holder.
Before programming, note the following:
Program a positioning block for the starting point (hole
center) in the working plane with RADIUS
COMPENSATION G40.
Program a positioning block for the starting point in the
tool axis (set-up clearance above the workpiece surface).
The algebraic sign for the parameter total hole depth
determines the working direction.
The TNC calculates the feed rate from the spindle speed.
If the spindle speed override is used during tapping, the
feed rate is automatically adjusted.
The feed-rate override knob is disabled.
ú Setup clearance (incremental value): Distance
between tool tip (at starting position) and workpiece
surface
ú Total hole depth (incremental value): Distance
between workpiece surface (beginning of thread) and
end of thread
ú PITCH :
Pitch of the thread. The algebraic sign differentiates
between right-hand and left-hand threads:
+ = right-hand thread
– = left-hand thread
Retract tool if program is interrupted (not TNC 410)
If you interrupt program run during tapping 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.
8.3 Dr
illing Cy
cles
X
Z
Example NC blocks:
N18 G85 P01 2 P02 -20 P03 +1*
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