HEIDENHAIN TNC 320 User Manual page 105

4.6 THREAD MILLING (Cycle 262,
DIN/ISO: G262)
Cycle run
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 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.
3 The tool then approaches the thread diameter tangentially in a
helical movement. Before the helical approach, a compensating
motion of the tool axis is carried out in order to begin at the
programmed starting plane for the thread path.
4 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.
5 After this, the tool departs the contour tangentially and returns to
the starting point in the working plane.
6 At the end of the cycle, the TNC retracts the tool at rapid traverse
to the setup clearance, or—if programmed—to the 2nd setup
clearance.
HEIDENHAIN TNC 320 105