HEIDENHAIN TNC 620 (81760x-02) ISO programming - Manual (Page 483)

Datum setting with 3-D touch probe (option 17) 14.10
14
TNC 620 | User's ManualDIN/ISO Programming | 2/2015
483
Circle center as datum
With this function, you can set the datum at the center of bore
holes, circular pockets, cylinders, studs, circular islands, etc.
Inside circle:
The TNC probes the inside wall of a circle in all four coordinate axis
directions.
For incomplete circles (circular arcs) you can choose the
appropriate probing direction.
Position the touch probe approximately in the center of the
circle
Select the touch probe function: Press the
PROBING CC soft key
Select the probing direction or press the soft key
for the automatic probing routine
Probing: Press the machine START button. The
touch probe probes the inside wall of the circle
in the selected direction. If you are not using the
automatic probing routine, you need to repeat this
procedure. After the third probing operation, you
can have the TNC calculate the center (four touch
points are recommended)
Terminate the probing procedure and switch to the
evaluation menu: Press the
EVALUATE soft key
Datum: In the menu window, enter both
coordinates of the circle center, confirm with the
SET DATUM soft key, or write the values to a table
(see "Writing measured values from the touch
probe cycles in a datum table", page 466, or see
"Writing measured values from the touch probe
cycles in the preset table", page 467)
Terminate the probing function: Press the
END soft
key
The TNC needs only three touch points to calculate
outside or inside circles, e.g. for circle segments.
More precise results are obtained if you measure
circles using four touch points, however. You should
always preposition the touch probe in the center, or
as close to the center as possible.