Evaluation of optimum combinations of spreading and cutting machines in a garment factory

This paper proposes a two-level model by using a nonlinear integer programming model and queuing theory with the Kendall-Lee A/B/C/D/E/F notation to assist garment manufacturers to evaluate their existing combinations of spreading and cutting machines installed in the cutting floor. The first level is a nonlinear integer programming model to determine the optimal number of spreading and cutting machines constrained by a given arrival rate of jobs and the service rate of the machines. The second level is used to determine the total cost of delay with the proposed number of machines which is given by the first model. In order to obtain the solution of this two-level model, M/M/1/GD/c/∞ and M/M/s/GD/c/∞ queuing theory models are applied on the second-level model and case studies are used to illustrate its application. The proposed approach is worthwhile for those manufacturers who intend to make a big investment in automation on their cutting floor.