Design And Implementation Of Dynamic Preventive Maintenance Method For Welding Automatic Production Line

With the rapid development of the modern automobile manufacturing industry, more and more complex equipments were used in the welding automatic production line. Growing complexity of the equipments would lead to a higher probability of equipment failure. The excessive number of shutdowns caused by equipment failure would affect the capacity of enterprises. Therefore, researching on preventive maintenance of Welding automatic production line’s equipment, so that the failure rate of the equipment remaining within the acceptable range, had become an urgent demand for automotive manufacturing enterprises. The preventive maintenance of equipment needed the history of the equipment information to predict the future trend of the equipment failure rate,in order to develop a reasonable maintenance strategy based on the prediction results. So there were two important research aspects in this thesis: Establishment and optimization of failure rate prediction model and maintenance strategy model of welding automatic production line’s equipment.This thesis has carried on the following research work around these two aspects.Firstly, the method for calculating failure rate of equipment was analyzed, and the core content of the method for calculating failure rate was determined from the analysis process: extracting the fault characteristic parametes of equipment. Therefore, this thesis studied and analyzd the structure and failure characteristics of the welding automatic production line’s equipment and combined with the FTA, AHP and FMECA methods, in order to determine the fault characteristic parameters of equipment. In the case of monitoring the fault characteristic parameters of equipment, the failure rate of the equipment could be calculated according to the monitoring values and the corresponding weight factors, which provided the input data for the equipment failure rate prediction model. Secondly, in order to improve the accuracy of the GM(1,1) model for the prediction of the welding production line equipment’s failure rate, this thesis improved it from two aspects: on the one hand, taking into count the key factors for predicting accuracy of GM(1,1) model is the background value parameter, the current background value calculation method is static and can’t adapt to the change of input datas, so this thesis turned the static background value calculation method into a dynamic one by combining the incremental PID feedback regulation algorithm, so as to improve its adaptability; on the other hand, the environmental impact factors of production line equipment were included in the prediction of failure rate. In this thesis, the GM(1,1) model was optimized by combining the above two methods. Furthermore, this thesis optimized the Fault cumulative distribution function based on Regression arithmetic model by combining with the failure rate prediction optimization model. According to the optimized distribution function, the single equipment maintenance planning model of welding automatic production line was constructed. Then in order to maximize the saving cost of system maintenance, a multi equipment maintenance planning model of welding production line was set up. Finally, the design and implementation of preventive maintenance system for welding automation production line was carried out.