Application Research On Parallel Machine Production Scheduling Considering Preventive Maintenance

Manufacturing is the main body of the national economy.Production scheduling is a key factor affecting the efficiency and quality of manufacturing.An effective scheduling solution can greatly increase the manufacturing efficiency of an enterprise and reduce its cost.Whereas the machine failures and repairing will make machine unavailable,which disorder the production scheduling directly.Therefore,the study of production scheduling must consider the failures and maintenance of the machine.Furthermore,the parallel machine scheduling problem is more flexible and complex than the single machine scheduling problem,and the randomness of the machine failure and the reliability requirements of producers further increase the complexity of parallel machine scheduling problem.In this paper,the production scheduling problem is discussed based on the machine deteriorating and preventive maintenance(PM)strategy to parallel machine systems.What`s more,the genetic algorithm is used to solve the problem.Based on the previous research of production scheduling,this paper makes the following work:First,considering the fact that new and old machines are coexisting in the actual production process due to the continuous deteriorating at different rates,the hazard rate increase factor and the age reduction factor are introduced to construct the failure rate rehearsal model to predict the system reliability.Considering minor repair costs,preventive maintenance costs,replacement costs,and relying on the system reliability,an imperfect preventive maintenance model is established.Then,based on the above maintenance strategy,parallel machine scheduling problem with maintenance constraints are studied.A scheduling model for jobs with variable processing time is constructed and the objective is to minimize the maximum completion time.A parallel machine scheduling scheme with pre-distribution thinking is proposed based on the principle of production balance and greedy algorithm,which greatly reduces the complexity of the problem.A pre-distribution model is constructed,of which the solution is used as input to construct the production scheduling model,so as to determine the machine assignment and job sequence.As the problem is proved to be NP-hard,the model is solved by genetic algorithm(GA).Finally,analyze the actual production process of a manufacturing company and optimize the existing process,which prove the feasibility of the proposed model in this paper.And the method with standard GA is compared with the proposed method in this paper to verify the effectiveness and economy.