| Popis: |
For complex products, as the size, shape, position and other properties of the geometric features changing, the accumulated assembly error or the coordination error between different assemblies would be affected directly. How to keep these key geometric characteristics in a statistical state, especially in the process of batch production, is an important factor to ensure error consistency. Aiming to control the assembly quality, optimization methods for key characteristics of aircraft products with feedback actions and ASFF (Assembly Station Flowing Fluctuation) analysis is proposed. Firstly, by collecting and constructing statistical quality samples, based on SPC (Statistical Process Control) method, criteria on abnormal assembly quality was analyzed, with qualitative practical experience. Secondly, four specific assembly controlling actions with a feedback loop were adopted by quantitative analysis, including PCF (Product Coordination Feature) identification, PCE (Process Coordination Element) mapping, CR (Coordination Relationship) modelling, and assembly error propagation modelling. Thirdly, the concept of ASFF was proposed, and the trajectory chart was plotted to evaluate the deviation and fluctuation of assembly error under one assembly station. This analysis was done by calculating the process offset and stability, according to the dynamic change of assembly quality status data at different time stages. Finally, with the specific improvement actions, i.e. (1) diagnosing the abnormal sources and improving the assembly operating process, (2) analyzing the dynamic deviation and fluctuation of assembly quality data within a specified assembly station, and (3) improving the assembly assurance ability, the out-of-tolerance problem of the skin profile was optimized to verify methodology's feasibility. Benefit results are gained, i.e. the locating state of ending ribs was more accurate, and the assembly process became more stable. With the rapid growth of aircraft production, the quality controlling method would be much helpful especially in the batch manufacturing stage. |
