Two Multi-Point In-Situ Measuring Methods Of Cylindrical Profiles And Uncertainty Analysis

Large cylinders are commonly used to roll large-sized products,such as super calendered paper,flat panel displays,solar panels and automotive steel.Such a cylinder should have the characteristic of high form accuracy,because cylindrical profile error will be copied to the product and result in product surface defects.Therefore,today’s equipment manufacturing industry urgently needs in-situ precision cylindricity measurement methods so as to improve the technical level of major national equipment manufacturing and market competitiveness of large-size products.The topic selected is faced with two multi-point cylindricity error separation techniques proposed by our research team.Two techniques can be used for the in-situ precision measurement of cylindrical profiles.In this dissertation,reliability and accuracy of the two techniques were evaluated by assessment of the measurement uncertainty and comparison with the measurement results of Talyrond 365.Researches are of great significance to promote the integration of cylindrical profile measurement technology with major manufacturing equipment,and to achieve integration of measuring and processing.Researches are as follows:1)The traditional three-point roundness error separation method was studied again based on the relationship between cross-sectional profile of the measured cylinder and its harmonic components.It was proved that the method can accurately measure the cross-sectional radius deviation and roundness,but its first-order harmonic suppression makes it difficult to accurately determine the least squares center vector of each cross-sectional profile.2)Based on the proposed two five-point configuration strategies,the corresponding error separation models were established.The theory and simulation proved that the two techniques can correctly determine the least squares center vector of each cross section,that is,the median line profile of the measured cylinder is accurately determined.The cylindrical profile measurement and reconstruction conforming to the definition of ISO 12180 is realized based on the median line profile.Error motions of the guide rail and the spindle system during measuring are eliminated,and the full harmonic error separation is realized.3)In view of the complexity of the two error separation algorithms,thetraditional evaluation uncertainty method based on differential calculation is unrealistic.The Monte Carlo method was selected to evaluate the measurement uncertainty of cross-sectional roundness and radius deviation as well as the straightness of the median line of the cylinder.The measurement uncertainty evaluation result shows the difference in anti-interference ability between two techniques.4)Comparing the measurement results of the cylindrical profile obtained by the two techniques with that of Talyrond 365,the five-point error separation method(FC-EST)was verified to have strong anti-interference ability and high measurement accuracy.Based on MATLAB,the simulation software and measurement uncertainty evaluation software for the two techniques have been developed,and the comparative experiments with the measurement results of Talyrond 365 have been executed.The research results obtained can be used as a reference for high precision in-situ measurement of large cylindrical profiles.