The Application Of Tolerance Allocation For The Aircraft Automatic Assembly Line

Tolerance analysis technology is an advanced technology which can ensure the size and shape of the coordination of exchange of tooling and tooling, tooling and products, product components and parts. According to the dimension chain model, key control those parts position accuracy which mostly influent the final target of assembly dimension accuracy, as the analysis basis for coordination problems in the process of assembly quality tracking when the process control, and to control the data of these statistics as the product quality and continuous improvement on the basis of stability control. Tolerance analysis methods used in this paper is based on the certainty analysis. First, establish the dominant function between positioning point deviation and assembly deviation. Second, according to the actual distribution of parts size deviation, generate a set of pseudo random numberby Monte Carlo simulation method. Third, put the pseudo random numbers into the assembly deviation model to calculate the arange of assembly deviation. Fourth, calculate the central moment of assembly dimensionon each order when enoughassembly deviation datas are gartheredand then fit approximate size distribution. And finally, calculate the deviation according to the distribution of measurement feature.By combining the computer aided modeling technology and tolerance analysis technology, software of tolerance analysis, AVA, was developed. And by using this software, the assembly deviation simulation analysis on civil aircraft middle fuselage was successfully done before the production line was put into production in commission.This paperanalysised the assembly deviationlayer by layer, from parts to sub-assemblies, from sub-assemblies to the middle fuselage assembly, determined thebest tolerance design for the middle fuselageautomatic assembly line, realized the fuselage panelautomatic drilling and riveting and fuselage final automatic assembly based on digitalmeasurement technology. Up to now, the production line has entered the final installation, debugging and acceptance stage, and the full-scale production of middle fuselage has been started. Therefore, this research got the actual verification.