The Research Of Quality Control Method On Multi-parameter Coupled Manufacturing Process

Allusion to multi-stage, complicated processes, high manufacturing cost, many influencing quality factors and difficulty varriation diagnosis et al, this thesis takes multi-stage manufacturing process for objects to research on process quality control method.Fistly, this thesis introduces the background and development of quality cotrol in the world, which indicates the limitations of traditional quality control method, Meanwhile, which also shows the importance of process quality cotrol in the future.Secondly, this paper analyses the structure and feature of multi-stage manufacturing process and the manufacturing process qaulity fluctuation rule. Due to multi-stage manufacturing process belonging to discrete time-varying dynamic system, this thesis establishs the basic variation transfer model using the state space equation, once more, which maps manufacturing process variation's influencing relation to the basic variation model in oder to establish the variation transfer model using homogeneous transformation.The qulity stability, controllability and observability of multi-stage manufacturing process was investigated for transformation from production to process in qulity control, and the condition of judgement of which were calculated based on the variation transfer model.According to fixture locating variation directily impacting the quality in multi-stage manufacturing process, this reseach aims to get a systematic method for fixture adjustment to minimize total production costs, which also establishs a mathematic model for the tolerance optimal allocation. finally, the source of quality variation was solved by the concept of using virtual process to further making sure the quality of the products.Two cases study were provided to illustrate the availability of the method in this thesis. The results show that the proposed model has a good performance for quality control in the multi-processes manufacturing process.