Operations Management: An Integrated Approach, 5th Edition

SCHEDULING BOTTLENECKS

When companies schedule a job shop, bottlenecks are common. A bottleneck is any resource whose capacity is less than the demand placed on it. For example, let's consider Akito's Flowers, a retail florist. When a customer orders flowers, three steps follow. First, the clerk takes the order and processes payment. Second, the clerk gives the order to the flower arrangers, who gather the appropriate materials and do the flower arrangement. Third, the drivers deliver the flowers. At Akito's Flowers, the clerk can process 30 telephone orders per hour. Each of the three flower arrangers can make 7 arrangements per hour, and each of the three drivers can make ten deliveries per hour. The flower arrangers are the bottleneck in this process. Regardless of the number of orders processed by the clerk, the arrangers can do a maximum of 21 arrangements per hour, and Akito's can deliver no more than 21 floral arrangements per hour. Thus the output of the process is reduced to the capacity of the bottleneck. Bottlenecks typically result when one operation in a job takes longer than the other operations.

Techniques for scheduling bottleneck systems emerged in the late 1970s with the introduction of optimized production technology (OPT) by Eli Goldratt. OPT classifies resources as either bottlenecks or nonbottlenecks, and makes bottlenecks the basis for scheduling and capacity planning. According to OPT, companies should schedule bottleneck resources to full capacity and schedule ...