production scheduling optimization algorithm for the steel-making continuous casting processes

This paper investigates the steel-making continuous casting (scc) scheduling problem. scc is a high temperature and large-scale process with batch production at the last stage that was identified as the key process of modern iron and steel enterprises. this paper presents a mathematical model for scheduling the scc process. the model is developed as a mixed zero-one linear programming (mzolp) according to actual situations of scc. the objective is scheduling a set of charges (jobs) to minimize the earliness and tardiness penalty costs as well as the charge waiting time cost. the solution methodology is developed based on a branch and bound (b&b) algorithm. a heuristic method presented at the beginning of the search to compute an initial upper bound. a lower bound and an upper bound are developed and a method for reducing branches is established based on the batch production in the continuous casting (cc) stage. moreover, branching schemes are proposed. the b&b algorithm presenting the initial upper bound, the lower and upper bound, the method for reducing branches, and branching schemes is tested on a set of instances. the analysis shows the efficiency of the proposed features of the algorithm.