HEIDENHAIN TNC 426B (280 472) ISO programming - Manual (Page 176)

8 Programming: Cycles 160
TAPPING NEW with floating tap holder
(Cycle G206, only with TNC 426, TNC 430 with
NC software 280 474-xx)
1 The TNC positions the tool in the tool axis at rapid traverse FMAX
to the programmed set-up 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. If you have entered a
2nd set-up clearance, the tool subsequently moves to that
position in FMAX.
4 At the set-up clearance, the direction of spindle rotation reverses
once again.
Before programming, note the following:
Program a positioning block for the starting point (hole
center) in the working plane with RADIUS
COMPENSATION G40.
The algebraic sign for the depth parameter determines
the working direction.
A floating tap holder is required for tapping. It must
compensate the tolerances between feed rate and
spindle speed during the tapping process.
When a cycle is being run, the spindle speed override
knob is disabled. The feed rate override knob is active
only within a limited range, which is defined by the
machine tool builder (refer to your machine manual).
For tapping right-hand threads activate the spindle with
M3, for left-hand threads use M4.
8.3 Dr
illing Cy
cles
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