Maintenance Strategy Of Car Crankshaft Automatic Production Line

Automatic production line has been adopted by more and more manufacturing enterprises because of its high yield,good quality and low labor cost.Production line is an important part of manufacturing system,whose production capacity related enterprise interest closely,so reasonable maintenance strategies need to be used to improve the reliability of production line.At present,the equipment maintenance strategies often exist two major problems,namely “insufficient maintenance” and " excessive maintenance"." Insufficient maintenance" can not effectively reduce the failure rate of equipment,"excessive maintenance" will result in high maintenance costs.Therefore,reasonable maintenance strategy for the production line need to be developed,which has great value and significance.This research was supported by the National Science and Technology Major Projects— "Car Crankshaft Automatic Production Line(2014ZX04002031)",took the crankshaft production line as the research object,optimized its maintenance strategy.Firstly,the equipment importance was divided according to the opinions of the maintenance experts and analyzing of fault data and maintenance data.Based on this,according to the delay time and reliability theory,a reasonable maintenance strategy of production line was given to reduce the downtime and maintenance costs and meet the reliability requirements of the equipment.The main contents of this paper were as follows:1.The car crankshaft production line was analyzed,including the processing technology,the structure of production line and the fault data collection method.In addition,the factors influencing the maintenance level of the production line were summarized and the problems existing in the current maintenance management were pointed out,which laid the foundation for further research.2.The importance of the equipment on the production line was determined.Four evaluation factors of equipment importance of production line were given: production rate factor,safety factor,maintainability factor and economic factor.First of all,the weight of the evaluation factors was determined by the AHP,then scores of each equipment under different factors were given through the expert scoring method.Finally,important equipments,secondary important equipments and general important equipments were determined according to the ABC classification.Preventive Maintenance was proposed for important equipments and secondary important equipments,Breakdown Maintenance was proposed for general important equipments.3.A method of the production rate factor scoring equipments was proposed.Firstly,the simulation model of the production line was established by the Plant Simulation software,then the test values of the failure rate of each equipment were given.The experimental scheme was optimized according to the uniform experimental design.Finally,the influence of the failure rate of each equipment on the production rate of the production line was analyzed by the regression analysis.The maintenance expert can score the production rate factor of each equipment according to the regression equation.This method simulated the actual situation of the production line,established the relationship between the equipment failure rate and the production line opening rate,which can make the result more accurate.4.Optimization the preventive maintenance cycle for important equipments.Under the requirement of reliability of important equipments,the optimal preventive maintenance model of important equipment was established according to the time delay theory,the optimal preventive maintenance cycle of important equipments was given.5.Optimization the preventive maintenance cycle for secondary important equipments.Based on the "maintenance cost-reliability" synchronous maintenance model,the preventive maintenance cycle of the secondary equipment was calculated,and the maintenance cost was minimized under the premise of satisfying the equipment reliability requirements.Finally,the preventive maintenance cycle of the secondary important equipment was corrected in conjunction with the important equipment preventive maintenance cycle.The revised model can greatly reduce the cost of preventive maintenance of the production line.The research of this paper solved the difficulty in determination of the preventive maintenance strategy in the enterprises,which has certain reference value for the enterprise equipment management and maintenance work.