L978 Workpiece Measurement Surface/Angle/Zo Determination (With And Without Differential Measurement) - Siemens SINUMERIK 840 User Manual

5 Measuring Cycles for Milling Machines and Machining Centres

5.4 L978 Workpiece measurement surface/angle/ZO determination (with and without differential measurement)

5.4 L978 Workpiece measurement surface/angle/ZO determination
(with and without differential measurement)
The measurement cycle makes it possible to measure blanks and zero offsets can be
determined automatically relative to the workpiece zero point.
Zero offset can be determined either at a surface by single point measurement or by means of
angular measurement between the blank (e.g. on a rotary table) and the main machine axes.
In addition, the cycle determines the dimensions of surfaces in relation to the workpiece zero
point by single point measurement or paraxial multipoint measurement and performs automatic
tool offset when necessary.
Differential measurements are also possible with this cycle.
Differential measurement means:
The measuring point (only the first measuring point in the case of paraxial multipoint
measurement and angular measurement) is measured twice with the spindle being rotated
through 180°, i.e. the probe is turned by 180° between the two measurements. In this way,
the trigger points are determined. The trigger point is stored in the MDC for the relevant axis
direction. An uncalibrated probe can therefore be used for measurement.
Preconditions for differential measurement:
• Oriented spindle stop (M19) by the NC
• Bidirectional/multidirectional probe
• Random positioning of probe in spindle between 0 and 360° (min. every 90°) (all-round
coverage).
• Monodirectional probe must be calibrated. Differential measurements cannot be
performed with this probe.
Selection is made by defining R23:
R23 = 0 ZO determination at surface
R23 = 1 Measure surface
R23 = 2 Paraxial multipoint measurement
R23 = 3 Angular measurement
R23 = 10 ZO determination at surface
R23 = 11 Measure surface
R23 = 12 Paraxial multipoint measurement
R23 = 13 Angular measurement
Applicable types of probe: (see Section 1.3)
• In the case of milling and machining centres the probe must be entered as type 30 in the
TOA memory.
• Multidirectional probe
• Bidirectional probe
• Monodirectional probe
5–66
with diff. measurement
with diff. measurement
with diff. measurement
with diff. measurement
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SINUMERIK 840/850/880 (BN)
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