HEIDENHAIN TNC 620 (340 56x-01) - Manual (Page 240)

240
8.2 Cy
cles f
o
r Dr
illing, T
apping and Thr
ead Milling
BORE MILLING (Cycle 208, Advanced
programming features software option)
1 The TNC positions the tool in the spindle 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.
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 set-up clearance at FMAX. If
programmed, the tool moves to the 2nd set-up clearance at FMAX.
Before programming, note the following
Program a positioning block for the starting point (hole
center) in the working plane with radius compensation R0.
The algebraic sign for the cycle parameter DEPTH
determines the working direction. If you program
DEPTH = 0, the cycle will not be executed.
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.
An active mirror function does not influence the type of
milling defined in the cycle.
Use the machine parameter displayDepthErr to define
whether, if a positive depth is entered, the TNC should
output an error message (on) or not (off).
Danger of collision!
Keep in mind that the TNC reverses the calculation for pre-
positioning when a positive depth is entered. This
means that the tool moves at rapid traverse in the tool axis
at safety clearance below the workpiece surface!