Research On Accuracy Analysis And Several Key Issues Of Micro Inner Scale Measurement System

With the rapid development of precision engineering, high technology and space technology, micro-scale parts are widely used in various industrial fields, requiring higher accuracy of processing and testing. While various countries are actively studying the precision measurement technology of micro inner scale, but due to lack of comprehensive and effective assessment of its accuracy, further development of the measurement and improvement is seriously hampered. Thus, this paper analysed the accuracy and studied several key issues of our own micro-scale measuring system, got more comprehensive and clearer understanding of uncertain factors impacted on the measurement result through analysis, so as to provide a reference and guidance to further improvement of measurement accuracy.Based on the theory of uncertainty evaluation, analyzed the uncertainty sources and their mechanism, established evaluation models, tested some influence parameters and got specific values. Measured the diameter of the hole which nominal diameter isФ0.3mm with aiming and triggering measurement way for many times. The diameter is in the cross-section which is 0.5 mm below the top of the hole. Using high-precision data compensation method to deal with the measurement results, and gave the assessment of combined standard uncertainty and expanded uncertainty. Main contents as following:(1)Based on comprehensive understanding of micro inner scale measuring system, including components, measuring principle and the measurement process, analyzed various uncertainty sources from three aspects including measurement equipment, measurement way, measurement environment and survey crew, established math models of their mechanism, provided the assessment of various uncertain sources.(2)Got specific value of various standard uncertainty by referencing and testing. For those parameters which can not be referenced, designed photoelectric testing methods based on national and local standards and norms, processed and evaluated test data.(3)In order to get accurate touch point in aiming and triggering measurement of micro inner scale, analyzed delay error and system drift of measurement system, proposed a compensation algorithm with higher precision based on data fitting, effectively reduced the effect of standard uncertainty due to aiming and triggering repeated measurement.(4)Measured the diameter which is in the specific cross-section of the micro hole that nominal diameter isФ0.3mm with aiming and triggering way, the result isФ297.07μm, the expanded uncertainty is 0.16μm (k=2).