HEIDENHAIN TNC 620 (34056x-04) Cycle programming - Manual (Page 122)

Fixed Cycles: Tapping / Thread Milling
4.10 OUTSIDE THREAD MILLING (Cycle 267, DIN/ISO: G267, software
option 19)
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TNC 620 | User's Manual Cycle Programming | 5/2013
4.10 OUTSIDE THREAD MILLING (Cycle 267,
DIN/ISO: G267, software option 19)
Cycle run
1 The TNC positions the tool in the tool axis at rapid traverse
FMAX to the entered set-up clearance above the workpiece
surface.
Countersinking at front
2 The TNC moves on the reference axis of the working plane from
the center of the stud to the starting point for countersinking
at front. The position of the starting point is determined by the
thread radius, tool radius and pitch.
3 The tool moves at the feed rate for pre-positioning to the sinking
depth at front.
4 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.
5 The tool then moves in a semicircle to the starting point.
Thread milling
6 The TNC positions the tool to the starting point if there has
been no previous countersinking at front. Starting point for
thread milling = starting point for countersinking at front.
7 The tool moves at the programmed feed rate for pre-positioning
to the starting plane. The starting plane is derived from the
algebraic sign of the thread pitch, the milling method (climb or
up-cut milling) and the number of threads per step.
8 The tool then approaches the thread diameter tangentially in a
helical movement.
9 Depending on the setting of the parameter for the number of
threads, the tool mills the thread in one helical movement, in
several offset helical movements or in one continuous helical
movement.
10 After that the tool departs the contour tangentially and returns
to the starting point in the working plane.
11 At the end of the cycle, the TNC retracts the tool in rapid
traverse to setup clearance or, if programmed, to the 2nd setup
clearance.