Analysis Of Measurement Data On BIW Accuracy Evaluation

With the development of automobile manufacturing,the body-in-white(BIW)precision has become an important research content for the automotive enterprises to evaluate the vehicle quality.Along with the continuous improvement of the equipment,the BIW measurement was more accurate and faster,and the data management was more standardized.By means of an advanced coordinate measuring technology to measure a BIW,by analyzing the measurement data to find out the main factors affecting the accuracy of the body,and by taking the targeted measures,the body accuracy have been improved.In this thesis,the equipment,the methods and the current situation in BIW measurement at home and abroad were investigated,and the domestic development trend was analyzed.From the angle of the process design,the influence of the stamping parts quality,the welding fixtures and the welding processes were studied on the BIW quality.Taking the actual production condition of a car from an automobile enterprise as an example,the sample data collected from the three coordinates were sorted and transferred for the analysis of the characteristics of measured data.The principal component analysis method was used to analyze the change trend of the data variables.The out-of-tolerance variables were studied and,combined with the linear equation,the dispersion and the time sequence diagram,the source of the error was found.The effective corrective measures were taken,having a positive guiding role for the quality control of the bodies.The improvement of the BIW size accuracy has been the important aims of the car factory.Under the market trend of the fine automobile quality,the quality control of a BIW also has been their important research direction for the brand manufacturers.The contents of this thesis were just a part of the whole BIW dimensional quality.The more influence from the welding processes and the corresponding equipment on BIW errors has yet to be further studied and discussed.