Research On The Key Technology Of Calibration Of Step Gauges For International Comparison

With the development of science and technology and the progress of society,especially the implementation of the national strategy of "made in China 2025" plan and "quality power",higher precision requirements are put forward for the widely used testing instruments and processing equipment(such as coordinate measuring machines,CNC machine tools,etc.)in the manufacturing industry.Step gauge is a common standard for calibrating coordinate measuring machines and CNC machine tools.Its measurement value is also one of the international key comparisons of geometric quantities carried out by the Bureau International des Poids et Mesures(BIPM).It is of great significance to carry out the research on the calibration technology of step gauge,improve the calibration accuracy of step gauge,and ensure the correctness and traceability of its quantity value transmission,so as to accelerate the development of industries related to step gauges,improve the quality of manufacturing products,and expand the international influence of measurement capability of China.In this dissertation,the current manufacturing situation and level of the step gauge of the international manufacturers are reviewed,and the calibration level and technical characteristics of the main national metrology institutes at home and abroad are analyzed,the main key technologies in step gauge calibration are summarized,and the design principles of calibration system are determined.Aimed on improving the accuracy of step gauge calibration,the theoretical problems and the key techniques affecting the calibration accuracy in the step gauge calibration are studied in depth,and the corresponding solutions are put forward in details.Finally,based on the above research work as a solid technical foundation,the accurate calibration of the step gauge is realized,and the calibration traceability system of the step gauge is established.Therefore,the main research work of this dissertation consists of the following parts.(1)According to the functional characteristics and technical requirements of the components of the step gauge calibration system,the design principles and objectives are determined,and the research focus and key technical issues are put forward.(2)A step gauge measurement model based on multi-path laser interference synthesis technology is proposed,and a step gauge calibration system is designed based on laser interferometer principle which can be directly traced to the national633 nm laser wavelength standard.The repeatability experiment and accuracy verification based on the second-level block are carried out.(3)A real-time measurement and correction method of air refractive index based on a special material etalon is proposed,which can quickly feedback the wavelength change under the measurement environment and improve the measurement accuracy of laser interference length.(4)The aiming technology based on the trigger probe is studied.And its performance evaluation and compensation method based on Abbé principle is proposed.The error calibration of the probe performance parameters is realized,and the calibration accuracy of the step gauge is improved.(5)The temperature monitoring,the repeatability and stability of measurement,and other experimental verification of the step gauge calibration system are completed,the measurement uncertainty of the calibration results is analyzed in detail,and the relevant verifications of calibration results are given to prove the accurate calibration of the step gauge and analysis of measurement uncertainty.The national step gauge value traceability system is established to realize the domestic unification and international equivalence of step gauge value.