X-ray Diffraction Stress Gauge Data Process Analysis Based On MSA

The development of modern equipment manufacturing industry requests better stressstatues of raw material and component, as well as stress measurement technique. X-raydiffraction method, a non-destructive stress measurement method widely used in research andapplication, is hardly to meet the demand of precise stress measurement. Data processing is anecessary step for X-ray diffraction method and has critical influence on its accuracy. Thestresses calculated by different methods with identical original data vary a lot, thus it issignificant to have a deep research on data processing.Measurement system analysis (MSA) is a popular theory to evaluate the error ofmeasurement system. By mathematical statistics and charts, it analyses resolution and error ofmeasurement system to find the main error source of system. It is a simple and effective erroranalysis method.This paper studied the peak search method of X-ray diffraction by repeatability andreproducibility of MSA. The experiment proves the maximum and parabolic methods havebest reproducibility and the cross-relation method has best repeatability. The standarddeviations of repeatability and reproducibility by same pear search method are same, provingthe apparatus, operator and operator-process interaction have same impact on system accuracy.With false measurement data, the robustness of the five peak-search methods is evaluated.The study indicates the gravity has best robust. The study also demonstrates the methodsadopted by experiment are better than the method used by the system.To assess the influence of fitting number of the least square method on results, the paper analysis the output of different fitting number by repeatability and reproducibility. The resultshows the curve gets smoother and warpage worsen as the fitting number become bigger.Smooth curve can reduce the difference between the change of stress and the theoretical value;while a warpage curve cause stress fluctuated severely and depress measurement accuracy.The warpage transition is between40to45, and the measurement become best when curvesare fitted in the transition. The use of repeated measurement data and the reproducibility ofthe measurement data, will be the40time the fitting effect and50fitting effect contrast, provethe40fitting better than50times the fitting effect.