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----------APPLICAZIONI LASER Number 4
April/May 2005----------- |
The laser systems increases the machine tool
performances by the measurement
of volumetric accuracy and dynamic coordination. |
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OPTIMIZE THE PRODUCTIVE
PROCESSES WITH FAST AND
ACCURATE MEASUREMENTS |
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| Specialized in the manufacture of laser instruments for machine tool
calibration, metrology, OEM
and many other industrial applications, OPTODYNE offer a range of
product that includes the
laser systems for the Volumetric measurement and calibration of
squareness, straightness and
linear positioning errors and for the non contact measurement of
circular and dynamic
coordination. Easy to setup and use, this solutions measure errors with
accuracy and quickly.
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by Mariarosa Colonnetti |
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The competition, in a global market as in the
today arena, needs to increase the machine tool performances in order to
obtain better productivity together with better cutted parts. With the
last generation of CNC controller it is possible to have high accuracy
even with less expensive machine. To achieve this result it is important
to measure the volumetric errors and compensate it. The vault key is to
measure those errors in fast and accurate way. In general it is not
enough to only compensate the machine for the linear error on the three
axes. There are many other errors as the straightness of the linear
guideway, the perpendicularity, the effect of the barycentre of movement
and of the counterbalance masses, that cause an error much higher the
three linear errors. The larger part of the modern CNC controllers offer
the capability for the volumetric compensation that is also called SAG
or CROSS compensation. The volumetric error can be used to generate the
volumetric compensation table that allow the CNC to compensate the
machine errors and to obtain an higher volumetric accuracy. |
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The sequential step or “Vector” method.
Using the laser “Vector”
(patent-pending) method, three errors for positioning, six for
straightness and three for squareness can be determinate in few ours
instead of some days, as using conventional techniques. The
fundamental point for the vector laser measurement technique is that
the direction of the laser beam (the measurement direction) is not
parallel to the movement direction. The results is that the measured
error is the sum of the linear positioning error and the error due
to the deviation from the ideal straight line. A method for the
application of this technique is to perform the step sequential
measurement. |
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laser beam is directed along the diagonal direction; instead of moving
the axes x, y and z continuously into the diagonal direction, the
machine is programmed for the the x axis movement, stop and take the
data, than move y, stop and take the data and successively move z stop
and take the data. The process is repeated till the opposite side of the
diagonal is reached; for this reason is called sequential step diagonal
measurement method. Most of the modern CNC have the possibility
toperform volumetric compensation (also called SAG or CROSS
compensation); the volumetric error can be used for the compensation
file generation that allow the CNC to compensate the machine errors
obtaining an higher volumetric accuracy. |
Most of the modern CNC have the possibility to
perform volumetric compensation (also called SAG
or CROSS compensation); the volumetric error can
be used for the compensation file generation that
allow the CNC to compensate the machine errors
obtaining an higher volumetric accuracy.
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