CMM尺寸测量的不确定度评定模型研究

研究了坐标测量机(CMM)尺寸测量的不确定度评定方法。建立了符合ISO国际标准的测量不确定度评定黑箱模型。利用测量系统分析的方法,对6项量值特性指标引入的不确定度分量进行量化分析或实验标定,依据产品几何技术规范给出了各不确定度分量的评定模型。最后,通过工件直径测量的不确定度评定实例验证该方法的可行性。实验结果表明CMM尺寸测量的不确定度主要来源是偏倚和线性,不确定度分量为1.88μm,是所有其他分量合成的2倍以上,而温度补偿引入的不确定度分量仅为0.04μm,在实际测量中可忽略不计。

Research on Uncertainty Estimation ModeI of CMM for Size Measurement

The method of uncertainty estimation of coordinate measuring machine( CMM)for size measurement is presented. Black box model,which complies with the specifications of ISO,is established for uncertainty estimation of CMM. Six quantum property factors and their quantification or calibration introduced by the uncertainty components are analyzed based on measurement system analysis. The evaluation models of uncertainty components are presented according to geometrical product specification( GPS). This method has proven to be feasible by the example of uncertainty estimation for diameter measurement of an experimental sample. Experimental result shows that the main source of uncertainty of CMM for size measurement is bias and linear,and its numerical value is 1. 88μm which is more than twice the combination of all the other uncertainty components. Moreover,the uncertainty component of temperature is only 0. 04 μm,it can be neglected in practice.