System Design On Repair Plan And Station Of Aviation Composite Structure

G is the world's leading supplier of civil aircraft structural parts,components,integrated systems and engines.Composite wing structure for aircraft A is workshop F's main product.In the process of ass production,the quality inspector found that about 20%of the structural part's assembly area thickness below the lower limit of tolerance.It was confirmed that the resin in the assembly area had flowed into the honeycomb during the curing process,therefore assembly area's thickness below the tolerance 0.1mm to 0.5mm.Because there is no way to completely prevent the resin from flowing into the honeycomb in the process of curing,it is urgent to repair the defects.However,there is no repair station in the workshop.In view of this situation,a reliable repair station is designed based on the repair method developed by workshop's engineers.The research content includes the repair plan schedulig,process design for repair station and quality improvement,specific research as follows:(1)In order to solve the repair plan scheduling problem,a scheduling goal which aim to maximize the repair number in a certain period of time is proposed,then a 0-1 integer programming model is established,and the ant colony algorithm is used to solve the model.Two different structural part selection rules are proposed in the ant colony algorithm,in which rule 1 mainly considers heuristic information corresponding to the repair number.On the basis of rule 1,heuristic information corresponding to the WIP cost and shipment delay is also considered in rule 2.Based on the current parameter settings,through the calculation of different examples,rule 1 is better than rule 2 in maximizing the repair number and reducing WIP cost,and rule 2 is better in reducing shipping delay,therefore,the current scheduling rule should be rule 1.(2)Based on the principle of clear and complete traceability of defective parts and repair records,develop a clear on-line and off-line operational process for the quality inspector,process engineer,quality engineer and foreman.Next?the existing repair method is transformed into a specific repair process,including the division and optimization of processes,repair tools and material selection.Finally,the layout of the repair station is planned.Because several stations require specialized processing equiplent,for the purpose of reducing costs,they are arranged in the corresponding station of main production line.At the same time,the polishing,wet lay-up,bagging and measuring stations are arranged in a place which have the advantange of convenient logistics transportation.According to the equipment and worker's needs of the work area,the internal layout of the four stations is designed.(3)In order to reduce the unflatness rate of repair surface,six sigma method is used.First in the definition phase the surface unflatness is identified.Sencond,the effectiveness of surface flatness measurement system is tested during the measurement phase.Third,in the analysis phase,from four potential factors,through experimental design and data analysis,the result show that factor B(vacuum bag pressure)have a significant effect on the surface unflatness.Fourth,in the improvement phase,an improved proposal for increasing a fiberboard and controlling the air pressure in the vacuum bag is pesented,which is verified by the experimental design and the regression analysis.Fifth,in the control phase,a detailed plan is proposed,the regular operational data is collected to monitor repair part's quality and ensure the repair process statistic controllable.Finally,the repair process's sigma level for surface flatness increase to 3.15,and overall repair success rate increase to 93.3%.