工业 CT 长度测量误差校准的探索研究

摘要

An exploratory research on the length measuring error calibration of industrial CT is carried out to move forward on the traceability of industrial CT in dimensional measurement. The length measuring error of industrial CT can be classified to two types:sphere distance error and plane distance error. For the widely accepted sphere distance error,a tiny forest-ball is developed,and calibrated by a high precision coordinated measuring machin. Then the tiny forest-ball is used to calibrate an industrial CT called Metrotom 1500,the sphere distance error is smaller than ± 2 μm,and smaller than the maximum permissible error of this machine. For the plane distance error,an exploratory experiment is conducted with steel gauge blocks and ceramic gauge blocks,and the plane distance error is out of the maximum permissible error. The experiment result shows that it is very different to calibrate the length measuring error of industrial CT by sphere distance and plane distance,and the plane distance error is much larger than sphere distance error when measuring a same length.%针对工业 CT 在尺寸测量领域难以溯源的问题，对工业 CT 长度测量误差的校准方法进行了探索研究。工业 CT 的长度测量误差分为球心距误差和端面距误差两类。对于球心距误差，研制出一种小森林球标准器，并使用微纳坐标测量机对其进行了校准。该标准器用于型号为 Metrotom 1500的工业 CT 的校准时，球心距误差小于±2μm，且小于仪器的最大允许误差。对于端面距误差，分别选用常见的金属量块和陶瓷量块作为尺寸实物标准器进行了探索实验，测得端面距误差超出了仪器的最大允许误差。实验结果表明，使用球心距和端面距校准得到的工业 CT 的长度测量误差差异很大，并且对于同一长度，端面距误差远大于球心距误差。