HEIDENHAIN TNC 620 (340 56x-01) User Manual
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8.2 Cy
cles f
o
r Dr
illing, T
apping and Thr
ead Milling
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 of the cycle parameters depth of thread
or sinking depth at front determines the working direction.
The working direction is defined in the following
sequence:
1st: Depth of thread
2nd: Depth at front
If you program a depth parameter to be 0, the TNC does
not execute that step.
If you change the thread depth, the TNC automatically
changes the starting point for the helical movement.
The type of milling (up-cut/climb) is determined by the
thread (right-hand/left-hand) and the direction of tool
rotation, since it is only possible to work in the direction of
the tool.
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!