Quality Magazine - March 2009 - (Page 40) | Q UA L I T Y T E S T & I N S PE C T I O N | easy • accurate • automatic ALL NEW A measuring uncertainty budget offers security for customer commitments and provides notes on minimizing measurement deviations. certificate and is reduced using the factor k = 2 (P = 95%) to a standard uncertainty of 165 nanometers (nm). • The measured value resolution 0.1 µm, comparable with the graduation. With the limit value a = 0.5 x resolution and assumed triangular distribution (b = 0.41), there is an estimated type B standard uncertainty of 20.5 nm. • The repeatability of the measurement was determined by taking 50 measurements on the standard. The calculated standard deviation sg of 59.1 nm entered in the measuring uncertainty budget for the test equipment as type A standard uncertainty. • The systematic measurement deviation (bias) of the measuring system, throughout the partial measuring range under observation, was determined as the difference of the average Pg of the measurements on the standard to determine the repetitive precision to the calibrated diameter xm of the level standard. The measurement error determined in this way is considered a limit value and is transformed under the assumption Table 1 Optical shaft measuring system (device no. 10 1006 08) Measuring range (in mm): Diameter of 0.2 to 140; length < 500; resolution 0.1 µm; Permissible deviation values (device error limits) MPE = (2 + D / 100) µm; D in mm Measuring Properties DSP Sensor The Ultimate in Handheld Laser Profilers of a standard distribution (b = 0.33) to a standard uncertainty of 9.11 nm. The course of the systematic measurement deviations of the measuring system within the permissible limit values was determined by the certified standard (see Figure 3). MEASURING UNCERTAINTY BUDGET The measuring uncertainty budget illustrates that significant parts of the comparatively low combined standard uncertainty of 198 nm for the shaft measuring system used results from the calibration uncertainty of the standard (69%) and the systematic measurement deviation of the measuring system (21%). The comparison of the standard uncertainty of the test equipment with the diameter tolerance indicates that the optical gage is suitable for the measuring task at hand. With comparable measuring conditions, the smallest testable diameter tolerance in the nominal dimension range with this shaft measuring system is 2.978 micrometers. The high measuring accuracy and the repetitive precision of the measuring system during automated diameter Run it in Standalone Mode •No cable, no tether to an external device •Use as a data collector or Go/No-Go Gage •View and save data •Integral battery 4 hour run time •Weighs 20 ounces with battery Or Use it as a USB Device With Your Laptop or Tablet PC •Enhanced graphics and data analysis •Automatically save every scan •Run inspection routines •Compare results from different algorithms on the same scan Test Object (Gear Shaft) ø 38.12 (hard-turned) Test equipment (values in µm) Test processes (values in µm) UPM (MPE) 1.380 l Bias l 0.276 Sg 0.059 UPM 0.198 Tmin 2.978 Uobject 0.473 U 1.180 Tmin 5.900 ø 33.35 (hard-turned) 1.353 0.256 0.070 0.198 3.490 0.189 0.798 3.992 ø 25.40 (hard-turned) 1.307 0.316 0.061 0.201 3.026 0.382 1.041 5.209 ø 34.0 (ground) 1.357 0.256 0.070 0.198 2.971 0.400 1.065 5.328 www.origintech.com 256-461-1313 ø 33.7 (ground) 1.355 0.256 0.070 0.198 2.971 0.608 1.405 7.026 ø 25.0 (ground) 1.305 0.316 0.061 0.201 3.026 0.144 0.763 3.816 Source: Hommel-Etamic America Quality Quick Clicks 415 at qualitymag.com 40 QUALITY | March 2009 www.qualitymag.com http://www.origintech.com http://www.qualitymag.com http://www.qualitymag.com
For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.