An assignment model of workers and machines to factories with considering air pollution factor and commuting fare

This paper presents a novel mixed-integer non-linear programming model forassigning workers and machines among a group of factories by considering air polluting rate ofmachines. This model has been formulated based on a cellular manufacturing system (CMS) undera dynamic environment where the product mix and part demands are varying during a multiperiodplanning horizon. A compromising aspect of this model is considering the commuting fareand the air pollution factor in assigning workers and machines to factories in order to reducing thetravelling fare of workers and air pollution of factories in crowded area of a city. Other componentsin objective function to be minimized are the total costs of inter-factory material handling, machinerelocation, machine overhead and machine processing, hiring and firing workers, and workerssalary.The proposed model incorporates several design features including alternate processroutings, operation sequence, processing time, production volume of parts, duplicate machines,machine capacity, worker assignment,hiring and firing workers, worker capacity, worker costs,commuting distance between workers and factories, transferring parts between factories in batch,air pollution factor, and commuting fare. A numerical exampleis solved by the Lingo software toillustrate the performance of this model.