HEIDENHAIN TNC 620 (340 56x-01) - Manual (Page 261)

HEIDENHAIN TNC 620 261
8.2 Cy
cles f
o
r Dr
illing, T
apping and Thr
ead Milling
HELICAL THREAD DRILLING AND MILLING
(Cycle 265, Advanced programming features
software option)
1 The TNC positions the tool in the spindle axis at rapid traverse
FMAX to the programmed set-up clearance above the workpiece
surface.
Countersinking at front
2 If countersinking is before thread milling, the tool moves at the
feed rate for countersinking to the sinking depth at front. If
countersinking is after thread milling, the tool moves at the feed
rate for pre-positioning to the countersinking depth.
3 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.
4 The tool then moves in a semicircle to the hole center.
Thread milling
5 The tool moves at the programmed feed rate for pre-positioning to
the starting plane for the thread.
6 The tool then approaches the thread diameter tangentially in a
helical movement.
7 The tool moves on a continuous helical downward path until it
reaches the thread depth.
8 After this, the tool departs the contour tangentially and returns to
the starting point in the working plane.
9 At the end of the cycle, the TNC retracts the tool at rapid traverse
to the set-up clearance, or—if programmed—to the 2nd set-up
clearance.