User`s manual for cycle programming

HELICAL THREAD DRILLING/MILLING (Cycle 265, DIN/ISO: G265) 4.9

HEIDENHAIN | TNC 640 | User’s manual for cycle programming | 9/2015

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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 or sinking depth at front determines the

working direction. The working direction is defined in

the following sequence:

1. Thread depth

2. 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.

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!