Circle center as datum, 8 d a tum set ting with 3-d t o uc h pr obe – HEIDENHAIN TNC 620 (340 56x-02) ISO programming User Manual
Page 341

HEIDENHAIN TNC 620
341
12.8 D
a
tum Set
ting with 3-D T
o
uc
h Pr
obe
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 automatically probes the inside wall in all four coordinate axis 
directions.
For incomplete circles (circular arcs) you can choose the appropriate 
probing direction.
U
Position the touch probe approximately in the center of the circle
U
Select the probe function by pressing the PROBING
CC soft key
U
To probe the workpiece, press the machine START
button four times. The touch probe touches four 
points on the inside of the circle
U
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 the 
measured values from touch probe cycles in datum 
tables", page 332, or see "Writing the measured 
values from touch probe cycles in the preset table", 
page 333)
U
To terminate the probe function, press the END soft
key
Outside circle:
U
Position the touch probe at a position near the first touch point 
outside of the circle
U
Select the probe direction by soft key
U
To probe the workpiece, press the machine START button
U
Repeat the probing process for the remaining three points See 
figure at lower right
U
Datum
: Enter the coordinates of the datum and confirm your entry
with the SET DATUM soft key, or write the values to a table (see 
"Writing the measured values from touch probe cycles in datum 
tables", page 332, or see "Writing the measured values from touch 
probe cycles in the preset table", page 333).
U
To terminate the probe function, press the END soft key.
After the probing procedure is completed, the TNC displays the 
coordinates of the circle center and the circle radius PR 
X
Y
X+
X
Y+
Y
X
Y
X+
X
Y+
Y
