HEIDENHAIN TNC 426B (280 472) ISO programming - Manual (Page 173)

157 HEIDENHAIN TNC 410, TNC 426, TNC 430
BORE MILLING (Cycle G208, only with the TNC 426,
TNC 430 with NC software 280 474-xx)
1 The TNC positions the tool in the tool axis at rapid traverse 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 drills 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 rapid traverse. If
you have entered a 2nd set-up clearance, the tool subsequently
moves to that position in rapid traverse.
Before programming, note the following:
Program a positioning block for the starting point (hole
center) in the working plane with RADIUS
COMPENSATION G40.
The algebraic sign for the cycle parameter TOTAL HOLE
DEPTH determines the working direction.
If you have entered the bore hole diameter to be the
same as the tool diameter, the TNC will bore directly to
the entered depth without any helical interpolation.
8.3 Dr
illing Cy
cles
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