Study On Bottleneck Identification And Scheduling In Job Shop

The Capacity of Bottleneck Machine determines the output of production system,so it's very important to identify bottleneck machine accurately and maximize bottleneck's capacity,by that,it can improve the outputs and benefits.But there are two deficiencies in current bottleneck identification study,one is the bottleneck identification and scheduling study is separation,and bottleneck is identified by single index.The two deficiencies resulting inaccurate bottleneck machine and can't get optimal scheduling scheme.Paper take the job shop as study object to solve the two deficiencies,through analysis the relationship of bottleneck identification and scheduling,paper put out the study combination point,then a new definition of bottleneck is put forward,and then build the bottleneck utilizing and identification model which change the study logic,bottleneck utilizing first and then identify bottleneck which is opposite to traditional logic.Firstly,build the job shop processing simulation model in plant simulation software,and optimize the scheduling by genetic algorithm to get the optimal scheduling scheme which is the foundation information of bottleneck identification.Secondly,analyze the shortages of current bottleneck identification indexs,build a bottleneck identification index system,then bottleneck identification becomes a multiple attribute evaluation problem,run the optimal scheduling scheme in plant simulation to obtain the parameter values of each index,then entropy weight method is used to get the weight of each index,and TOPSIS method is used to evaluate each machine to get the bottleneck machine.Thirdly,considering scheduling scheme based 100% bottleneck machine utilization is not optimal scheme when there are many interference factors in production system,Bottleneck Available Rate(BAR)is put forward,set some different BAR level and implement BAR in plant simulation to get the optimal scheduling scheme under interference environment,then analysis the completion time and look for optimal BAR with interference factors in production system.At last,the paper take a 10 workpieces and 10 machines scheduling as study example to verify the effectiveness of the bottleneck identification and utilizing model which is put forward in paper,and analysis the influence law of BAR to scheduling by setting interference factors to provide guidance for practical production.