Research On Production Scheduling Integrated With Equipment Maintenance For Single Machine Group Production

With the rapid development of economic globalization and industrial technology and the improvement of people’s living standard,people’s demand for the quality of life as well as product diversity is getting higher and higher.In order to adapt to the competitive market demand,enterprises must produce many varieties of small batch products at a low cost.In this context,group production is widely used in the manufacturing industry.Production scheduling and equipment maintenance management are two important parts of enterprise operation management.Production scheduling and equipment maintenance management level determines the operating costs and operational efficiency of enterprises,and directly affects the competitiveness of enterprises.The two affect each other,complement each other.If only the production scheduling is considered,the equipment will be worn out due to overuse,the effective age of equipment will increase and so on,which results in the decrease of machining precision and machining efficiency,ultimately affects the product quality and delivery time.If only the equipment maintenance is considered,the original production scheduling will be interrupted because of the maintenance activities.Therefore,it is necessary to research the integration of the production scheduling and equipment maintenance.This paper studies a single machine group production system.Based on the current research on production scheduling,equipment maintenance and the integration of the two studies,a comprehensive analysis is given,which summarizes the disadvantages of the existing research.Then,by using the theory of statistics,optimization and other multidisciplinary theory,the integration of production scheduling and equipment maintenance is studied.Finally,a practical optimization model integrated production scheduling and equipment maintenance is put forward to comprehensively make decision about scheduling sequence,maintenance mode,preventive maintenance time.According to the research framework,the following work are finished in this paper:(1)The influence factors of workpiece processing time are quantified.In this paper,the influence of the learning and forgetting effects on the processing time is quantified by using the similarity of parts and the influence of equipment deterioration effect on the processing time is quantified by using the deterioration factor and equipment effective age.Based on this,a practical processing time model considering the learning and forgetting effects and the equipment degradation effect is established.(2)The scientific hybrid maintenance strategy is identified.In order to improve the reliability of equipment,preventive maintenance based on the perfect maintenance mode is adopted in this paper.While the minimum maintenance mode based on equipment age is adopted in order to deal with unexpected equipment failure during batch processing to make the equipment restore normal running state.And the appropriate preventive maintenance time is determined based on the failure rate threshold in order to effectively avoid excessive and insufficient maintenance.(3)The optimization model integrated production scheduling and equipment maintenance is built.Based on the comprehensive consideration of the interaction between the processing time model and the equipment maintenance strategy,a multi-objective optimization model integrated production scheduling and preventive maintenance for group production is proposed to minimize total completion time and maintenance cost.In this paper,based on the mathematical characteristics of the optimization model,the genetic algorithm is designed to solve the integrated model,including designing coding mode with constraints and genetic operation,uniforming the dimensions of time and cost,setting weights to construct fitness function.Finally,a numerical example is given to verify the feasibility and effectiveness of the integrated model.