The ISO-10360 standard has existed since 1994. This standard covers acceptance and reverification tests for Coordinate Measuring Machines (CMMs). While operators use other standards internationally, ISO-10360 is the most rigorous, giving buyers confidence in their equipment.
There are three uncertainties tested under ISO 10360:
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Volumetric length measuring uncertainty (MPEE)
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Volumetric probing uncertainty (MPEP)
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Volumetric scanning error (MPETHP)
These tests are useful not only for verifying the accuracy of newly bought equipment but also for ongoing maintenance and recalibration. When manufacturing parts require strict tolerances, it is vital the measuring equipment used is as accurate as possible. Regular testing and recalibration keep CMMs operating within these strict limits.
Tests for Measuring Arm Specifications
The ISO-10360 includes several tests for measuring arms. These tests have exact specifications to ensure CMMs operate with maximum accuracy. There are four standard tests and three more tests for measuring arms with a scanner. The tests are as follows:
Size/Form Error on a Sphere, Tactile
This test has two results. It uses 25 measuring points and compares the result of the measurements to the calibrated size and form of the sphere. CMM operators perform the test twice, and if the results differ, they treat the worst of the two results as the final test result.
Articulated Location Error, Tactile
This test measures errors caused by the articulation of the arm, in particular errors associated with axes 5, 6 and 7 of the joint. This test is done by probing five points of a sphere with the probe pointing in a specific direction, then adjusting the probe and repeating the process for five different orientations. CMM operators perform this test with the sphere in two different positions for maximum accuracy.
Length Measurement Error, Unidirectional, Tactile
This test determines the unidirectional error when CMM operators measure the distance between two points. They figure out this error by measuring in 105 lengths, taking the arm's articulation into account. The error result is not an average but rather the greatest error out of all measured lengths.
SPAT
CMM operators perform this test by placing the probe into a cavity, then moving the elbow from left to right. As they move the elbow, they take 10 measurement points. The test result is the radius of the smallest sphere that encompasses all 10 points.
Form and Size Error, Scanning
CMM operators use this test for laser scanners on a fixed 3D measuring apparatus, and it is a part of the ISO-10360-08 standard. It is similar to the first form/size test listed above. However, operators use the scanner base and arm in place of the CMM.
Articulated Location Error, Scanning
Operators also use this test for laser scanners on a fixed 3D measuring apparatus. They use this test to determine the accuracy of contactless scanning. The test involves measuring a calibrated sphere in five different orientations. They then calculate the center of each sphere. The test result is the radius of the smallest sphere that can encompass all five center points.
It's important to note not to designate this test to determine the scanner's accuracy but rather the influence of any movement of the scanner arms on the measurements.
Length Measurement Error, Unidirectional, Scanning
This is the final test for laser scanners. It is similar to the Length Measurement Error, Unidirectional, Tactile test. However, instead of using a probe, it uses a scanner. The test takes 105 measurements, resulting in the greatest measurement error.
Conclusion
By using ISO-10360 calibration, companies can easily compare the performance and accuracy of the CMM machines they use. In addition, they can feel confident any new machines they purchase are accurate. Many machines test to VDI/VDE 2617 or ASME B89, and these standards are not as exacting as ISO-10360.
Having confirmation you can rely on for these machines is crucial to stay within ISO-10360 standards. If you need to repair or calibrate your CMM, take a look at the high-quality, reliable parts from Metrology Parts.