HEIDENHAIN TNC 426, User Manual

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HEIDENHAIN TNC 426, TNC 430 239
8.3 Cy
cles f
o
r Dr
illing, T
a
pping and Thr
ead Milling
THREAD MILLING/COUNTERSINKING
(Cycle 263)
1 The TNC positions the tool in the tool axis at rapid traverse FMAX
to the programmed setup clearance above the workpiece surface.
Countersinking
2 The tool moves at the feed rate for pre-positioning to the
countersinking depth minus the setup clearance, and then at the
feed rate for countersinking to the countersinking depth.
3 If a safety clearance to the side has been entered, the TNC
immediately positions the tool at the feed rate for pre-positioning
to the countersinking depth
4 Then, depending on the available space, the TNC makes a
tangential approach to the core diameter, either tangentially from
the center or with a pre-positioning move to the side, and follows
a circular path.
Countersinking at front
5 The tool moves at the feed rate for pre-positioning to the sinking
depth at front.
6 The TNC positions the tool without compensation from the center
on a semicircle to the offset at front, and then follows a circular
path at the feed rate for countersinking.
7 The tool then moves in a semicircle to the hole center.
Thread milling
8 The TNC moves the tool at the programmed feed rate for pre-
positioning to the starting plane for the thread. The starting plane
is determined from the thread pitch and the type of milling (climb
or up-cut).
9 Then the tool moves tangentially on a helical path to the thread
diameter and mills the thread with a 360° helical motion.
10 After this, the tool departs the contour tangentially and returns to
the starting point in the working plane.