| Manufacture process quality is the important foundation to realize designing intention and assure product quality, the process quality control has become precession technique of enterprise's quality improving. In order to improve quality and reduce cost, the fluctuation produced around the design target is farthest controlled and reduced, a predetermined quality target is realized to the best of our abilities. How to establish the connection between quality target and process quality control, thus insure the realization of the quality target, it gradually becomes the focus that is cared by international quality control researcher and practitioner.A quality-oriented statistical process control approach is put forward by this dissertation, therefore a bridge is set up between predetermined quality target and scene process quality control by researching of this method. The manufacture process quality control based quality target is realized. The predetermined quality target is realized in production process. Its using value lies in realizing mechanical product higher quality and precision with craft cost and apparatus condition the same as traditional method, the operable and standardized new method is offered for effectively and quantificationally controlling nonconforming rate of pivotal working procedure, there are great realistic meanings to improve the level of product quality and manufacture precision in mechanical manufacturing industry of our country. The main work and innovative achievement of this dissertation are as follows:1,According to the requirements of establishing quality target, the quality target and quality evaluation system that could fill the request of different quality control. A set of standardized process quality indices for variables is introduced for meeting the measurement and evaluation to process yield, process centering and quality loss, the standardized process quality indices value system is presented based on raisonne grading by using the geometrical series of preferred numbers and arithmetical series.2,The expression of quality-oriented statistical tolerance and quality-oriented statistical tolerance zones are studied, the quantitative requirement of three levels statistical tolerance and quality control are summarized. Standardized method is offered for choosing process quality target, designing statistical process control chart parameter, designing sampling plan based on a required confidence probability. Function development and connotation promotion of this statistical tolerance is realized, to develop a quality-oriented statistical process control approach, a standardized interface between process quality indices system and the parameter design of control charts is needed.3,On the basis of the research of quality-oriented statistical tolerance, a quality-oriented statistical process control approach is put forward. The design and application flow of quality-oriented conventional control chart is studied. For more efficient detecting small in the process mean, the Cumulative Sum (CUSUM) Control Chart and the exponentially weighted moving average (EWMA) control chart is studied, an optimization design parameters and application flow of CUSUM control chart and EWMA control chart are designed to make the chart have the best average run length performance. This kind of method is improvement of the traditional statistical process quality control.4,The preliminary application study of the quality-oriented statistical process control approach is realized. The further expansion and deepen of this theory method is realized by the form of software system. Combining the development of the workshop integrated quality system project, the popularization and application of this method is explored tentatively. By analyzing system run, make the manufacture process is in real-time monitored, make sure that the rational improvement of the quality target could be realized in controlled process condition.
|
PDF Full Text Request