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Introduction
Geomet Versions - 6.66.006.001
Integrating the U/V Rotary Axis Table into your inspection requires only
that the enable state is turned on. By default, the rotary axis is disabled
when Geomet starts, or restarts. The DRO will continue to report the current
position, but the rotation of an axis will not be applied to the current
coordinate system.
Activating the U/V Rotary Axis Table
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*See Below |
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| Keyboard |
Main Menu |
Toolbar |
During the inspection process the axis enable state can be toggled on or off
based on the current inspection requirements. This is accomplished through the main drop-down menu:
[System® U/V Rotary Table Tools®
Activate U/V - Axis Coordinate System]
When the U/V Rotary Table is enabled there will be a check next to the menu command.
The Inspection Process - Building the Coordinate System
The key to a successful inspection is the strength of your coordinate
system. This is especially true when you add additional axes to the
calculation. The Part Coordinate System should be built using features that
represent the furthest extents of the part being measured.
Should you establish the Orient with a feature that represents only 10% of
the length, then the potential error is magnified 10x over the full length.
Should that error be 0.0001", then the error at the full length of the part
is 0.001"! When you add in the U/V axes, the error magnifies. For example,
if you are using a 14,400 count per revolution encoder, each count
represents a table movement of 0.0052" at 12.0" from the rotation axis!
When specifying the rotary table, always calculate the allowable error at the
maximum dimension you expect to inspect at. If the 14,400 counts per
revolution that delivers a potential error of 0.0052" at 12.0"
might exceed your
requirements, consider a change to the encoder. An encoder that offers
40,000 counts per revolution results in a 0.0019" error at 12.0".
When you build the part coordinate system, it is recommended that you
minimize table rotations. By eliminating the U/V axes from the calculations,
the part coordinate system becomes more stable and you will have a higher
certainty of the reported results.
The Inspection Process - Applying Rotation
The real benefit of the U/V Rotary Axis Table is the ability to rotate the
inspected part to access any feature at any orientation. Thus expanding your
inspection and reducing the time it takes to perform an inspection.
When the table is rotated, Geomet updates the incoming XYZ data to reflect
the change in U/V rotation. This can be demonstrated simply by watching the
DRO when the axis is rotated. While the XYZ position of the CMM is not
moved, the rotation of either axis shows the XYZ reported position changing
with regard to the current coordinate system.
During the inspection process, when you spread the data points evenly around
a feature, such as a cylinder, you ensure the greatest possible accuracy.
For best results, the data points should be distributed the full length of
the cylinder and around the circumference of the cylinder a full 360°.
Without the assistance of the rotary table it is not always possible to
reach the full extent of the cylinder due to limited access to the feature,
or the relationship to the orientation of the probe.
In the case of an inside diameter cylinder passing through a part, rotating
the part to align the axis of the cylinder with the alignment of the probe
you can then capture data points on one end of the cylinder over the full
360° circumference. Then rotate the part to provide access to the
opposite end and complete the data point capturing. Now the data points are
spread over the full extent of the cylinder. This will provide better
position, size and form reporting of the cylinder.
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