HEIDENHAIN TNC 620 User Manual page 525

Touch Probe Cycles: Automatic Tool Measurement | Fundamentals
probingFeedCalc (No. 122710) determines the calculation of the
probing feed rate:
probingFeedCalc (No. 122710) = ConstantTolerance:
The measuring tolerance remains constant regardless of the tool
radius. With very large tools, however, the feed rate for probing
is reduced to zero. The smaller you set the maximum permissible
rotational speed (maxPeriphSpeedMeas No. 122712) and the
permissible tolerance (measureTolerance1 No. 122715), the
sooner you will encounter this effect.
probingFeedCalc (No. 122710) = VariableTolerance:
The measuring tolerance is adjusted relative to the size of the tool
radius. This ensures a sufficient feed rate for probing even with
large tool radii. The TNC adjusts the measuring tolerance according
to the following table:
Tool radius
Up to 30 mm
30 to 60 mm
60 to 90 mm
90 to 120 mm
probingFeedCalc (No. 122710) = ConstantFeed:
The feed rate for probing remains constant; the error of
measurement, however, rises linearly with the increase in tool
radius:
Measuring tolerance = r • measureTolerance1/ 5 mm, where
r:
measureTolerance1:
HEIDENHAIN | TNC 620 | User's manual for cycle programming | 10/2017
Measuring tolerance
measureTolerance1
2 • measureTolerance1
3 • measureTolerance1
4 • measureTolerance1
Active tool radius in mm
Maximum permissible error of
measurement
18
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