Study On Robust Design And Optimization Technology Of Civil Aircraft Manufacturing Process Based On Six Sigma

C919 civil aircraft is an important manifestation of the development of comprehensive technical capacity in our country, while higher requirements of current aircraft are put forward for safety, economy and long life. Therefore, how to improve the overall level of manufacturing technology and capacity and how to protect quality are particularly important. The use of new materials, new technologies and new processes brings a huge challenge for the aircraft development cycle, so how to master new materials technologies in a fast and efficient way has become one of major bottlenecks in the development process of the C919.A new type of lightweight aluminum alloy material with excellent mechanical properties, high strength, high damage, etc.. becomes an important structural material of large civil aircraft. But during the process, it is found that its chemical milling process cannot meet the technical requirements of surface roughness and grain end of the corrosion. Its manufacturing process needs to be improved as soon as possible. Therefore, this paper focuses on this new aluminum alloy and develops matching research of material and process based on traditional process. Meanwhile, the robust design method of Six Sigma is introduced into R&D of process in order to explore the new design and optimization method of management theory combined with civilian aircraft manufacturing technology, so that the efficiency of R&D of process is improved.Following studies are carried out for new aluminum alloy chemical milling surface quality problems, combined with robust design of Six Sigma methods:First, combining Six Sigma theoretical basis with aluminum alloy chemical milling basic theory, Six Sigma quality management analysis method DMIC process is used to describe the unqualified phenomenon of surface roughness and of the corrosion during chemical milling process. Meanwhile, flow chart is used to determine the whole process analysis of “people, machines, materials, methods, environment and tests” which influence the milling quality. Results show that the main factor which influences chemical milling quality should be present in chemical milling process and formulation of the solution itself. Therefore, single-factor and two-factor tests of aluminum ion, sodium hydroxide and temperature are designed based on the existing production line of milling solution formulation system. The variance and reliability analysis of test plan and results are analyzed by Minitab software, so the influence of the chemical milling solution composition and temperature are determined.Secondly, on the basis of single-factor test, response surface experiments of chemical milling solution and process are designed. The variance in regression and isograms of response relationship among surface roughness, grain end of the corrosion and each factor are established. The scope of each solution component is determined. On this basis, in order to determine the scope, orthogonal response surface experiments are designed and results are analyzed by software. Interaction relations of each solution component are determined as well as solution composition.Finally, according to the solution composition and process parameters determined by test results, the production line solution formulations are improved. Meanwhile, the milling rate and corrosion ratio of the new aluminum alloy chemical milling are acquired. This data is used to verify the test pieces in the whole process of the new aluminum alloy production typical production line. The results meet production requirements and prove the reliability of the process.