9 bore milling (cycle 208), Cycle run, Bore milling (cycle 208) – HEIDENHAIN TNC 640 (34059x-04) Cycle programming User Manual
Page 92

Fixed Cycles: Drilling
3.9
BORE MILLING (Cycle 208)
3
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TNC 640 | User's Manual Cycle Programming | 3/2014
3.9
BORE MILLING (Cycle 208)
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 and then moves the tool to the bore hole circumference
on a rounded arc (if enough space is available).
2 The tool mills in a helix from the current position to the first
plunging depth at the programmed feed rate
F.
3 When the drilling depth is reached, the TNC once again
traverses a full circle to remove the material remaining after the
initial plunge.
4 The TNC then positions the tool at the center of the hole again.
5 Finally the TNC returns to the setup clearance at
FMAX. If
programmed, the tool moves to the 2nd set-up clearance at
FMAX.