HEIDENHAIN TNC 426B (280 472) Touch Probe Cycles - Manual (Page 88)

76 3 Touch Probe Cycles for Automatic Workpiece Inspection
3.3 A
u
to
matic W
o
rk
piece Measur
ement
MEASURE HOLE (touch probe cycle 421,
ISO: G421)
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 values in system parameters.
1 The TNC positions the touch probe to the starting points at rapid
traverse (value from MP6150 or MP6361) following the positioning
logic (see “Running touch probe cycles” on page 7) to the starting
point
1 . The TNC calculates the probe starting points from the data
in the cycle and the safety clearance from MP6140.
2 Then the touch probe moves to the entered measuring height and
probes the first touch point at the probing feed rate (MP6120 or
MP6360). 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:
2
3
4
1
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 from center of reference axis
Q162 Deviation from center of minor axis
Q163 Deviation from diameter
Before programming, note the following:
Before a cycle definition you must have programmed a
tool call to define the touch probe axis.