Decoupling the Confounded Effect of Machine Error and Geometric Characteristics of Artifacts in Precision Measurement and Machine Calibration

Abstract

Inspection is commonly used to scrutinize the quality of manufactured products against established standards and specifications. However, the quality and reliability of many inspection processes are contaminated by various measurement errors. One of the prominent sources for measurement error is the imperfection of the measuring device and its interaction with geometric characteristics of a measured feature. To ensure the quality and reliability of any inspection process, measurement errors need to be addressed for all data acquisition activities. A method is also needed to identify and decouple the effect of confounded errors. If this can be done, then the collected data can be adjusted properly to allow a more meaningful analysis. In this paper, the issue of measurement error identification and reduction for machine calibration and dimension measurement using artifacts with spherical features is discussed. Analytical models are derived to first assess and then decouple the confounded effect of imperfect measuring device and its interaction with geometric characteristics of a measured feature. Finally, case studies are used to illustrate the use and effectiveness of the methodology. [S1087-1357(00)00402-0]