HEIDENHAIN TNC 426, User Manual

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230 8 Programming: Cycles
8.3 Cy
cles f
o
r Dr
illing, T
a
pping and Thr
ead Milling
RIGID TAPPING without a floating tap holder
TAPPING (Cycle 207)
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:See “RIGID TAPPING (Cycle 17),” page 229.
1 The TNC positions the tool in the tool axis at rapid traverse FMAX
to the programmed setup clearance above the workpiece surface.
2 The tool drills to the total hole depth in one movement.
3 Once the tool has reached the total hole depth, the direction of
spindle rotation is reversed and the tool is retracted to the set-up
clearance at the end of the dwell time. and — if programmed — to
the 2nd set-up clearance with FMAX.
4 The TNC stops the spindle turning at set-up clearance.
Machine and control must be specially prepared by the
machine tool builder for use of this cycle.
Before programming, note the following:
Program a positioning block for the starting point (hole
center) in the working plane with radius compensation R0.
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.
At the end of the cycle the spindle comes to a stop. Before
the next operation, restart the spindle with M3 (or M4).