SEQUENCING WITH SETUP TIME AND ORDER TARDINESS TRADE-OFFS

We consider the problem of scheduling customer orders on a single faci lity where each order consists of several jobs that can be clustered i nto several groups. When a facility is changed over to another group, a setup time associated with the new group is required. Two particular problems are considered in this context. One is to consider the total setup time and the number of tardy orders jointly. The other is to co nsider the total setup time and the maximum tardiness jointly. The tot al setup time in both problems represents a measure of internal effici ency, whereas the number of tardy orders and the maximum tardiness rep resent a measure of external efficiency. In any shop, the decision mak er must consider the tradeoffs between large setup costs associated wi th a more frequent changeover schedule versus the cost of tardy orders that might be induced by a less-frequent changeover schedule. In this article branch-and-bound algorithms are proposed to identify the set of nondominated schedules fur the two bicriteria problems. (C) 1996 Jo hn Wiley & Sons, Inc.