Quick Guide to Precision Measuring Instruments
Coordinate Measuring Machines
Table 1 ISO 10360 Series Item
Performance Assessment Method of Coordinate Measuring Machines
ISO Standard No.
Year of issue
1 2 3 4
Terms
ISO 10360-1 ISO 10360-2 ISO 10360-3 ISO 10360-4 ISO 10360-5 ISO 10360-6
2000 2009 2000 2000 2010 2001
Length measurement
Regarding the performance assessment method of CMM, a revision of ISO 10360 Series was issued in 2003 and was partially revised in 2009. The following describes the standard inspection method including the revised content.
Rotary table equipped CMM
Scanning measurement
5 Single / Multi-styli measurement
6
Software inspection
Using the standard CMM with specified probe, measure 5 different calibrated lengths 3 times each in 7 directions within the measuring volume (as indicated in Figure 1), making a total of 105 measurements. If these measurement results, including the allowance for the uncertainty of measurement, are equal to or less than the values specified by the manu- facturer, then it proves that the performance of the CMM meets its specification. The result of OK/NG is required to be judged considering the uncertainties. The maximum permissible error (standard value) of the test may be expressed in any of the following three forms (unit: µm). Maximum Permissible Length Measurement Error E 0, MPE [ISO 10360-2: 2009]
Length meas. error 3 （ Z ）
Length meas. error 4
Length meas. error 5
Length meas. error 6
Length meas. error 7
Length meas. error 2 （ Y ）
Z
Z
Y
Y
X
X
Length meas. error 1 （ X ）
Figure 1 Measauring directions to obtain length measurement error
Note: ISO 10360-2: 2009 requires measurement in 4 different directions and recommends measurement parallel to each axis, while ISO 10360-2: 2001 specified the measurement "in 7 arbitrary directions."
A: Constant (µm) specified by the manufacturer K: Dimensionless constant specified by the manufacturer L: Measured length (mm) B: Upper limit value (µm) specified by the manufacturer
E 0,MPE (MPE E ) = A + L/K ≤ B E 0,MPE (MPE E ) = A + L/K E 0,MPE (MPE E ) = B
The following error definitions were added in ISO 10360-2: 2009.
In addition to length measurement in 7 directions, ISO 10360-2: 2009 specifies mea- suring in 2 lines over the diagonal YZ or XZ plane with probe offset as shown in Figure 2. Note: The stylus offset is set at 150 mm as default. Maximum Permissible Length Measurement Error/ Length Measurement Error when stylus offset is 150 mm E 150, MPE [ISO 10360-2: 2009]
Calculate the maximum value from the results of three repeated measurements. Maximum Permissible Limit of the Repeatability Range of Length Measurement R 0, MPL [ISO 10360-2: 2009]
6.0 4.0 2.0 0.0
R 0
-2.0 -4.0 -6.0
150 mm
Z
1 2 3
600 800 Standard value
Z
150 mm
0
200 400 Measurement length [mm]
Y
X or Y 軸
X or Y 軸
X
Figure 2 Length measurement error when Z-axis stylus offset is 150 mm
Figure 3 Repeating range of length measurement
Maximum Permissible Radial Four-Axis Error MPE FR , Maximum Permissible Tangential Four-Axis Error MPE FT , and Maximum Permissible Axial Four-Axis Error MPE FA [ISO 10360-3: 2000]
Z
Sphere B
L
Y
h B
r
X
The test procedure under this standard is to place two standard spheres on the rotary table as shown in Figure 4. Rotate the rotary table to a total of 15 positions including 0˚, 7 positions in the plus (+) direction, and 7 positions in the minus (-) direction and measure the center coordinates of the two spheres in each position. Then, add the uncertainty of the standard sphere shape to each variation (range) of radial direction elements, connecting direction elements, and rotational axis direction elements of the two standard sphere center coordinates. If these calculated values are less than the specified values, the evaluation test is passed.
h
Sphere A
h A
Figure 4 Evaluation of a CMM with a rotary table
L-23
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