Quick Guide to Precision Measuring Instruments

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PG67Quick Guide to MeasurementRegarding 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. The following error denitions were added in ISO 10360-2:2009.* ISO 10360-2:2009 species measurement in 4 different directions as essential and recommends measurement parallel to each axis, while ISO 10360-2:2001 specied the measurement "in arbitrary 7 directions."Figure 1 Measuring directions to obtain length measurement errorFigure 2 Length measurement error when Z-axis stylus offset is 150mmFigure 3 Repeating range of length measurementFigure 4 Evaluation of a CMM with a rotary tableTable 1 ISO 10360 seriesE0,MPE（MPEE）＝A＋L/K≦BE0,MPE（MPEE）＝A＋L/KE0,MPE（MPEE）＝BA: Constant (µm) specied by the manufacturerK: Dimensionless constant specied by the manufacturerL: Measured length (mm)B: Upper limit value (µm) specied by the manufacturer⎫⎬⎭Performance Assessment Method of Coordinate Measuring MachinesUsing the standard CMM with specied 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 specied by the manufac-turer, then it proves that the performance of the CMM meets its specication.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).In addition to length measurement in 7 directions, ISO 10360-2:2009 species measuring in 2 lines over the diagonal YZ or XZ plane with probe offset. Note: The stylus offset is set at 150mm as default.Maximum Permissible Limit in Repetitive Length Measurements R0, MPL [ISO 10360-2:2009]After measuring the given length 3 times, evaluate variation in measurement results. Then, calculate the repeatability range R0.Maximum permissible length measurement error E0,MPE [ISO 10360-2:2009]Maximum Permissible Length Measurement Error / Length Measurement Error when Z-axis stylus offset is 150mm E150, MPE [ISO 10360-2:2009]Maximum Permissible Limit in Repetitive Length Measurements R0, MPL [ISO 10360-2:2009]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 specied values, the evaluation test is passed.Maximum Permissible Rotation Axis Radial-Direction Error MPEFR, Maximum Permissible Rotation Axis Connecting-Direction Error MPEFT, and Maximum Permissible Rotation Axis Axial-Direction Error MPEFA [ISO 10360-3:2000]YrXhhAhBSphere BZSphere AItemISO Standard No.Year of issue1TermsISO 10360-1:200020022Length measurement*ISO 10360-2:200120013Rotary table equipped CMMISO 10360-3:20002000 4Scanning measurementISO 10360-4:20002000 5 Single/Multi-styli measurement**ISO 10360-5:200220026Software inspectionISO 10360-6:20012001* Revised in 2009 **Revised in 2010Length meas. error 3（Z）Length meas. error 4Length meas. error 7Length meas. error 5Length meas. error 6Length meas. error 1（X）Length meas. error 2（Y）ZYXZYXZ150mmX or Y軸ZXY6.04.02.00.0-2.0-4.0-6.00123R0200400Measurement length [mm]Error［µm］600800Standard value