Frame Calculation From Three Measuring Points In The Area, Meaframe - Siemens sinumerik 840d Programming Manual

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6.8 Frame calculation from three measuring points in the area,
840D 840D
NCU 571 NCU 572
NCU 573
6.8

Frame calculation from three measuring points in the area, MEAFRAME

MEAFRAME is an extension of the 840D language
used for supporting measuring cycles.
This function is valid in SW 4.3 and higher
Function
When a workpiece is positioned for machining, its
position relative to the Cartesian machine coordinate
system is generally both shifted and rotated referring
to its ideal position.
For exact machining or measuring either a costly
physical adjustment of the part is required or the
motions defined in the part program must be changed.
A frame can be determined by probing three points in
the area for which the ideal positions are known.
Probing is performed with a tactile or optical sensor
touching special holes or spheres that are precisely
fixed to the backing plate.
The function MEAFRAME calculates the frame from
three ideal and the corresponding measured points.
In order to map the measured coordinates onto the
ideal coordinates using a rotation and a translation, the
triangle formed by the measured points must be
congruent to the ideal triangle. This is achieved by
means of a compensation algorithm that minimizes the
sum of squared deviations needed to reshape the
measured triangle into the ideal triangle.
Since the effective distortion can be used to judge the
quality of the measurement, MEAFRAME returns it as
an additional variable.
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SINUMERIK 840D/840Di/810D/FM-NC Programming Guide Advanced (PGA) − 04.00 Edition
FM-NC 810D 840Di
Frames
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