坐标测量机面向任务的测量不确定度评定

基于产品几何技术规范,分析了坐标测量机面向任务的测量不确定度主要来源;重点讨论了量值特性指标测量复现性的定义与特点,并针对坐标测量机的测量任务,提出引起坐标测量复现性的主要因素,研究了进行复现性指标评价的实验方案,建立了复现性评定的数学模型;通过孔径测量实例分析,介绍了坐标测量机面向任务的测量不确定度评定方法。结果表明,孔径测量结果的合成标准不确定度为3.2 μm,其中测量复现性的不确定度分量高达2.5μm,在测量结果不确定度中所占比重最大。

Task-oriented Measurement Uncertainty Evaluation of Coordinate Measuring Machine

Based on geometrical product specification (GPS) and verification, the main sources of task-oriented measurement uncertainty of coordinate measuring machine (CMM) are analyzed. The definition and characteristics of reproducibility, which is one of CMM quantum property factors, are specially discussed. For the measurement task of CMM, the main factors that might cause measurement reproducibility are proposed, the experimental procedure to evaluate reproducibility value is studied, and the mathematical model for reproducibility evaluation is established. Furthermore, the approach to evaluate task-oriented measurement uncertainty of CMM is provided through an example of circle diameter measurement. The results of the example analysis show that the uncertainty component caused by reproducibility is up to 2.5μm when the combined standard uncertainty of circle diameter measurement is determined to be 3.2μm, and it is accounted for the highest proportion of the result uncertainty.