(108-2246-1-PB)A PROCESS ORIENTED QUALITY CONTROL APPROACH BASED ONDYNAMIC SPC AND FMEA REPOSITORY

摘要

To guarantee a constant quality of manufactured products, it is necessary to optimise the process parameters immediately when deviations of the workpiece quality have been observed. In most cases, it usually depends on the process knowledge and experience of the operators to adjust the parameters of the machine manually. Established methods of quality management are only able to register quality deviations or to analyse them offline with the help of experts. Although statistical process control (SPC) provide statistical techniques and graphical displays control charts to enable the quality of conformance to be monitored and special causes of process variability to be eliminated. However, this technology has been not all well applied in enterprises, and the main reason is the operators can't find the process is going to be out of control, and the root reason of quality problem may be hard to be determined according to the knowledge of the operators when the quality problem has appeared in manufacturing process Therefore, the presented approach develops a system which combined dynamic control chart with expert knowledge library. The expert knowledge library is built up based on the failure mode and effect analysis (FMEA) for the process oriented automated quality control. The system is carried out in two steps: the first step, a local quality controller stabilises the product quality to reference values in the pace of workpiece production,when the process is going to be out of control, the system will give a warning to remind operators to take action exactly and keep the process in normal; in the second step, the system can give the related information and valuable suggestions to operator and help them to take correct action to keep the process in control. The system application has shown the product quality level have been improved, and the cost lose of quality out of control had been prevented.