JJF(津) 65-2022 钢直尺检定仪校准规范

钢直尺检定仪校准规范CalibrationSpecificationforTesterofSteelRule2022―01―25发布2022―04―25实施天津市市场监督管理委员会发布天津市地方计量技术规范JJF(津)65—2022JJF(津)65—2022归口单位：天津市市场监督管理委员会主要起草单位：天津市计量监督检测科学研究院本规范委托天津市计量监督检测科学研究院负责解释钢直尺检定仪校准规范JJF(津)65—2022CalibrationSpecificationforTesterofSteelRuleJJF(津)65—2022本规范主要起草人：刘红光(天津市计量监督检测科学研究院)李青(天津市计量监督检测科学研究院)李凌梅(天津市计量监督检测科学研究院)陈洁(天津市计量监督检测科学研究院)参加起草人：王伟(天津市计量监督检测科学研究院)路瑞军(天津市计量监督检测科学研究院)马艺清(天津市计量监督检测科学研究院)何振环(天津市计量监督检测科学研究院)JJF(津)65—2022目录引言································································································（Ⅱ）1范围·····························································································（1）2引用文件·······················································································（1）3概述·····························································································（1）4计量特性·······················································································（2）4.1检定仪平台直线度········································································（2）4.2测量重复性···········································································（2）4.3示值误差···········································································（2）5校准条件·······················································································（2）5.1环境条件····················································································（2）5.2校准用设备及技术要求··································································（3）6校准项目和校准方法········································································（3）6.1检定仪平台的直线度····································································（3）6.2测量重复性·················································································（3）6.3示值误差·················································································（3）7校准结果表达·················································································（3）8复校时间间隔·················································································（4）附录A钢直尺检定仪示值误差测量结果的不确定度评································（5）JJF(津)65—2022引言JJF1071-2010《国家计量校准规范编写规则》、JJF1001-2011《通用计量术语及定义》和JJF1059.1-2012《测量不确定度评定与表示》共同构成本校准规范制定工作的基础性系列规范。本技术规范为首次制定。JJF(津)65—20221钢直尺检定仪校准规范1范围本规范适用于钢直尺检定仪的校准。2引用文件本规范引用了下列文件：JJF1001通用计量术语及定义JJF1097平尺凡是注日期的引用文件，仅注日期的版本适用于本规范；凡是不注日期的引用文件，其最新版本（包括所有的修改单）适用于本规范。3概述钢直尺检定仪（以下简称检定仪）是以影像测量为原理，光栅尺为基准元件，用于测量钢直尺的计量仪器。一般由检定仪平台、影像系统、位移传感器、测量软件等组成。其结构型式如图1。1-检定仪平台；2-影像系统；3-位移传感器；4-测量软件；5-被检钢直尺图1钢直尺检定仪结构示意图JJF(津)65—202224计量特性4.1检定仪平台直线度4.2测量重复性4.3示值误差5校准条件5.1环境条件温度：（20±3）℃，每小时变化不超过1℃；或按照仪器说明书规定。校准前，被校准的仪器在室内平衡温度时间不少于24h，校准用标准器在室内平衡温度时间不少于2h。5.2校准用设备及技术要求校准用设备及技术要求见表1。表1校准用设备及技术要求序号设备名称技术要求1电子水平仪分辨力0.01mm/m2标准金属线纹尺二等6校准项目和校准方法在进行仪器校准之前，首先进行外观检查，目测工作台和传感器没有影响校准工作的缺陷。必要时按照仪器使用说明书规定执行仪器的启动和准备程序。6.1检定仪平台的直线度按JJF1097平尺校准规范中相应方法进行校准。6.2测量重复性首先将标准金属线纹尺安置在检定仪平台上，在测量位置上调整影像系统，使线纹尺刻线均成像清晰，调整金属线纹尺的纵轴线与影像系统的运动方向平行，用影像系统分别瞄准0刻线及1000mm刻线，对0至1000mm线纹间隔进行测量，反复10次，计算这10个测得值的实验标准差作为仪器测量重复性。6.3示值误差JJF(津)65—20223按照6.2的方法安置标准金属线纹尺，测量各刻线相对于零刻线的线纹间隔，依次瞄准标准金属线纹尺的刻线并记录检定仪的测量数据，测得值与标准金属线纹尺实际值的差值作为测量结果，此为往测。然后立即反向进行返测，取两次测量结果的平均值作为最后结果。测量间隔：（0-10）mm中的每毫米间隔；（0-1000）mm中的每分米间隔。示值误差也允许采用满足测量不确定度要求的其他方法进行校准。7校准结果的表达经校准的钢直尺检定仪出具校准证书。校准证书内页至少应包含下列内容：校准条件；校准项目和校准结果；检定仪平台直线度；测量重复性；示值误差；示值误差的测量结果不确定度（评定方法见附录A）。8复校时间间隔复校时间间隔可由用户根据实际使用情况自主决定，建议不超过1年。JJF(津)65—20224附录A钢直尺检定仪示值误差测量结果的不确定度评定A.1测量方法钢直尺检定仪示值误差使用标准金属线纹尺进行校准。校准时，将1m标准金属线纹尺安置于工作台上，测量各刻线相对于零刻线的线纹间隔，测得值与标准尺实际值的差值作为测量结果。下面以校准钢直尺检定仪1000mm处示值误差为例，进行测量不确定度的评定。A.2测量模型cbeLL=−（A.1）式中：e——钢直尺检定仪的示值误差，mm；Lc——钢直尺检定仪的读数值，mm；Lb——标准金属线纹尺所用测量段的实际值，mm；A.3方差和灵敏系数因为各输入量彼此独立。依不确定度传播率，由式（A.1）得方差：22222c12()()()cbuecuLcuL=+式中：c()uL——测量重复性引入的标准不确定度分量；b()uL——标准器具引入的标准不确定度分量。灵敏系数：()()11==cecL()()2b1==−ecL故：222c()()()=+cbueuLuLA.4标准不确定度分量标准不确定度一览表见表C.1。JJF(津)65—20225表C.1标准不确定度一览表标准不确定度分量u(xi)不确定度来源标准不确定度ci()iicuxu(Lb)标准器具7.28μm17.28μmu1(Lb)标准金属线纹尺测量不确定度0.33μmu2(Lb)线膨胀系数差7.18μmu3(Lb)温度差1.15μmu(Lc)测量重复性0.49μm-10.49μmA.5标准不确定度计算A.5.1二等标准金属线纹尺引入的不确定度分量u1(Lb)根据二等标准金属线纹尺的检定证书，二等金属线纹尺的测量不确定度为U=（0.20+0.8L）μm（k=3），标准金属线纹尺引入的不确定度分量为：u1(Lb)=1.0μm/3=0.33μmA.5.2线膨胀系数差引入的不确定度分量u2(Lb)钢直尺检定仪光栅尺的线膨胀系数为(7.6±1.0)×10-6℃-1,证书给出的标准线纹尺线膨胀系数为(11.5±1.0)×10-6℃-1，两者差值的最佳估计值为3.9×10-6℃-1。温度偏离t=3℃的条件下，服从均匀分布，线膨胀系数差值引入的不确定度分量：61cz1m33.9106.75m33−−===℃℃μu线膨胀系数的不确定度会给测量结果带来影响，检定仪光栅尺和标准金属线纹尺线膨胀系数差的界限在±2.0×10-6℃-1范围内服从三角分布，t=3℃,线膨胀系数的不确定度引入的分量：61bq1m32.0102.45m66u−−===℃℃μ由此估算在1m处，线膨胀系数差引入的不确定度分量：()2227.18mczbbquuuL=+=μA.5.3温度差引入的不确定度分量u3(Lb)经充分等温后，标准线纹尺与检定仪光栅尺的温度差估计在±0.5℃范围内服从均JJF(津)65—20226匀分布，取α=4.0×10-6℃-1，由温度差引入的不确定度分量：()6311m0.54.0101.15m33buL−−===℃℃μA.5.4标准器具引入的不确定度分量u(Lb)()()()()2221237.28mbbbbuLuLuLuL=++=μA.5.5测量重复性引入的不确定度分量u(Lc)对标准线纹尺1000mm点的示值误差各进行10组测量，得到如下测量结果表C.2重复性测量表格测量次数12345测量值(mm)999.990999.991999.991999.992999.990测量次数678910测量值(mm)999.990999.990999.991999.990999.990采用贝塞尔公式计算标准差得到s=0.70μm，最终结果取两次测量平均值，重复性测量引入的不确定度分量为0.49m2s=μ，数显分辨力引入的不确定度分量为0.29μm，取两者的大值，即u(Lc)=0.49μmA.6合成标准不确定度22c()()()=7.30mcbueuLuL=+μA.7扩展不确定度取k=2，扩展不确定度为：c=14.615mUku=μJJF(津)65—2022