HEIDENHAIN TNC 320 (77185x-01) Cycle programming - Manual (Page 114)

Fixed Cycles: Tapping / Thread Milling
4.8 THREAD DRILLING/MILLING (Cycle 264, DIN/ISO: G264)
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TNC 320 | User's Manual Cycle Programming | 3/2014
Please note while programming:
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, countersinking depth or sinking depth at
front determines the working direction. The working
direction is defined in the following sequence:
1. Thread depth
2. Countersinking depth
3. Depth at front
If you program a depth parameter to be 0, the TNC
does not execute that step.
Program the thread depth as a value smaller than the
total hole depth by at least one-third the thread pitch.
Danger of collision!
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).
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 to set-up clearance below
the workpiece surface!