Research On Large-dimension Screw-thread Micrometers Proofreading Poles Calibration Device Design

The thread micrometer indication error measurement is performed by the thread micrometer proofing rod.Therefore,the accurate and reliable traceability of the thread micrometer proofing rod value value plays a decisive role in the measurement of the thread micrometer indication error.At present,the proofreading rod mainly adopts the measuring method specified in the national verification regulations,and the vertical optical meter and the measuring block are matched with the groove gauge and the three needles for detection.However,the vertical optical meter has a measurement range of only 175 mm,and there is no current effective technical specification for the measurement of a 175 mm threaded micrometer proofing rod.According to the practical application,this paper designs a large-scale thread micrometer proofing rod calibration device,which can measure the indication error of large and small thread micrometer proofing rods.The specific research content is as follows:(1)Analyzed the existing large and small-sized thread micrometer proofing rod measuring method,and proposed the design scheme of using the laser interferometer to measure on the measuring machine with self-designed needle gauge and needle gauge fixture,and set up and debug the calibration.Device.(2)Investigate the design principles and schemes of needle gauges and needle gauge fixtures,measure the dimensional limit deviations,shape and position tolerances of needle gauges and needle gauge fixtures,study the function relationship between the groove width of needle gauges and needle gauge fixtures,and the calibration rod and needle The positional relationship of the groove width of the gauge fixture reduces the influence on the measurement result.(3)The size parameters of the large and small size proofing rods are measured separately.The outlier value is excluded based on the outlier judgment rule,and the normalized deviation comparison method is used.For the proof rod with the measurement range less than 175 mm,The experimental data of this device is compared with the data measured by the vertical optical metering block.The error of the measurement results of the two devices does not exceed 0.5?m.For the proofing bar with the measuring range greater than 175mm,the data measured by the device and the image measuring instrument are used.For comparison,the error of the measurement results of the two devices did not exceed 1 ?m.Analysis of the experimental results shows that the measuring device is feasible.(4)The influence of various factors on the experimental results is analyzed,and corresponding correction processing is performed during the experiment.The measurement results after the correction processing are accurate and reliable.The measurement method proposed in this paper can detect large and small threaded micrometer proofing rods.This calibration device achieves full coverage of the calibration rod size measurement range and provides more accurate measurement results.The calibration device has the advantages of simple structure,convenient operation and reliable result,and provides a good reference for the error measurement of the large and small-sized thread micrometer proofing rod.