Lot streaming in [N-1](1)+N(m) hybrid flow shop

This paper deals with N-stage hybrid flow shop (HFS) lot streaming problem to develop a schedule that minimises the makespan. The HFS considered consists of one machine in each of the first (N-1) stages and m machines in stage N. A mixed integer linear programming (MILP) model is proposed and solved using LINGO solver. For large size problems, the LINGO solver takes longer time and hence an algorithm is proposed. The heuristic approach consists of splitting the lots and then sequencing. The lot splitting is based on the average processing time of jobs in the first (N-1) stages and cycle time of stage N. The sum of processing time of all jobs in each stage of the first (N-1) stages is considered for sequencing. Numerical illustrations are carried out to show the percentage deviation of solution obtained using the algorithm from the MILP model. The results show that the algorithm gives near optimal solution to the problems within a very small computational time compared to the MILP model.