HEIDENHAIN TNC 640 (34059x-04) Cycle programming - Manual (Page 501)

MEASURE HOLE (Cycle 421, DIN/ISO: G421) 17.5
17
TNC 640 | User's Manual Cycle Programming | 3/2014
501
17.5 MEASURE HOLE (Cycle 421, DIN/ISO:
G421)
Cycle run
Touch Probe Cycle 421 measures the center and diameter of a hole
(or circular pocket). If you define the corresponding tolerance values
in the cycle, the TNC makes a nominal-to-actual value comparison
and saves the deviation value in system parameters.
1 Following the positioning logic, the TNC positions the touch
probe at rapid traverse (value from FMAX column) (see
"Executing touch probe cycles", page 410) to touch point 1 . The
TNC calculates the touch points from the data in the cycle and
the safety clearance from the SET_UP column of the touch
probe table.
2 Then the touch probe moves to the entered measuring height
and runs the first probing process at the probing feed rate
(column
F). The TNC derives the probing direction automatically
from the programmed starting angle.
3 Then the touch probe moves in a circular arc either at measuring
height or at clearance height to the next starting point 2 and
probes the second touch point.
4 The TNC positions the probe to starting point 3 and then to
starting point 4 to probe the third and fourth touch points.
5 Finally the TNC returns the touch probe to the clearance height
and saves the actual values and the deviations in the following
Q parameters:
Parameter number Meaning
Q151 Actual value of center in reference
axis
Q152 Actual value of center in minor axis
Q153 Actual value of diameter
Q161 Deviation at center of reference axis
Q162 Deviation at center of minor axis
Q163 Deviation from diameter
Please note while programming:
Before a cycle definition you must have programmed
a tool call to define the touch probe axis.
The smaller the angle, the less accurately the TNC
can calculate the hole dimensions. Minimum input
value: 5°