| To remain competitive in the global market and meet customer demands for high quality and low cost products, industries have been changing to run a multi-specification and small-batch production mode. . But it is a challenge to statistical process control (SPC) in complicated and changeful manufacturing environment , because traditional SPC only applies to large batch production. The dissertation makes a systematic and profound research on the method, application strategy of SPC, and process adjustment method. Embedded SPC system is developed in complicated and changeful environment. Last, this system is applied successfully in bear ferrule manufacturing.The whole thesis is divided into seven chapters.Chapter one, the significance of quality control in modern manufacturing industry was described. The development of statistical quality control, process adjustment and integrated SPC are introduced, and then the research topic is put forward about this thesis.Chapter two, under the background of multi-production, small-batch and the development of network technology, the SPC methods of process quality monitoring are analyzed, especially EWMA control chart based process model, The capability and parameters optimization of EWMA control chart is systematically and profoundly studied . The process quality monitoring system based on the network level of multi-bus is set up using embedded and network technology.Chapter three, from the concept of group technology (GT), statistical cluster is studied using average run length (ARL) of EWMA control chart as index, the mixed sample space S based on statistical clustering is formed, control chart of mixed sample space S is annalyzed. Statistical cluster criteria are developed using boundary restriction and multi attribute decision making (MADM), the strategy of forming a part family and using a uniform EWMA control chart in one part family . In the end of this chapter, the basic criteria and the steps of application of statistical cluster are introduced.Chapter four, Process Adjustment is an important method for improving manufacturing quality, This chapter researchs process adjustment method and its application strategy. First,the model of manufacturing process is set up using Kalman filter method; Index function LC(n)of Energy Smooth Grade for evaluating quality process is studied. Application strategy of proposed adjusting is given, integration of SPC and process adjustment is realized. This method is validated with simulated data and practice.Chapter five, with development of network, especially Internet/ Intranet, process quality control is changed from separated control to comprehensive and concentration-separation's quality control. This chapter studies key technology and problems about the system frame of embedded SPC system facing network environment, software organization, system real-time and safety.Chapter six, Considering the characteristic of grinding work-procedure an embedded SPC system for manufacturing miniature bearing ferrule is studied. This system also includes the control and measurement of geometry dimension, surface roughness and form. Optimizing design method based LVDT sensor and on-line compensating technology to improve measuring precision is given. The software design and realization of embedded SPC unit is discussed. The capability of embedded SPC unit is evaluated by measuring system analysis. The result shows that this system has stable performance, high precision, network function, large data memory andlow price.Finally, chapter seven makes a conclusion of the whole dissertation and puts forward the future research in this field.
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