HEIDENHAIN TNC 640 (34059x-05) Cycle programming - Manual (Page 163)

CIRCULAR STUD (Cycle 257, DIN/ISO: G257) 5.7
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TNC 640 | User's Manual Cycle Programming | 1/2015
163
5.7 CIRCULAR STUD (Cycle 257, DIN/ISO:
G257)
Cycle run
Use Cycle 257 to machine a circular stud. The TNC mills the circular
stud with a helical infeed motion starting from the workpiece blank
diameter.
1 If the tool is below the 2nd set-up clearance, the TNC retracts
the tool to the 2nd set-up clearance.
2 The tool moves from the stud center to the starting position for
stud machining. With the polar angle you specify the starting
position with respect to the stud center using parameter Q376.
3 The TNC moves the tool at rapid traverse FMAX to the set-up
clearance Q200, and from there advances to the first plunging
depth at the feed rate for plunging.
4 The TNC then machines the circular stud with a helical infeed
motion, taking the overlap factor into account.
5 The TNC retracts the tool from the contour by 2 mm on a
tangential path.
6 If more than one plunging movement is required, the tool
repeats the plunging movement at the point next to the
departure movement.
7 This process is repeated until the programmed stud depth is
reached.
8 At the end of the cycle, the tool departs on a tangential path and
then retracts in the tool axis to the 2nd set-up clearance defined
in the cycle.