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Rolling Through Time

In requirements planning environments, as a result of the limited visibility into the future, the manufacturers often plan their replenishment schedules on a rolling horizon basis. Using the currently available data, they determine their best replenishment quantities over a specified planning horizon and implement a subset of the earlier replenishment decisions. After rolling through time, the schedules are updated utilizing recently collected data.

Application of rolling schedules is common in industry; however, appropriate use of rolling schedules requires careful consideration as it poses many challenges for channel integration. First of all, one needs to be aware of the limitations of rolling schedules. Even if the best possible replenishment schedule is determined in each planning cycle, the long-term replenishment schedule may not necessarily represent the best possible schedule. This is usually the result of the length of each planning cycle. If each cycle is not long enough, it is not possible to determine the best replenishment schedule that would be found knowing demand beyond the end of the planning cycle.

(Supply Chain Coordination Through Schedule Integration, Sahin F., 2008, Page #1)

First Day Load

When resources have excessive loads the workload will be pushed backward until the load on the first day is greater than the available capacity. Such a condition is referred to as a first-day-load peak and reveals the presence of a constraint resource.

(Manufacturing planning and control for supply chain management, Vollman T.E., Page #558)

Dyad by Dyad Approach

A dyad by dyad approach means that pairs of organizations jointly develop the new processes and MPC systems that allow them to ever more effectively integrate their detailed operations. It is dyad by dyad because the joint working and definitions of improvement projects will tend to be unique to the dyad. This said, best practice will be able to learn as mush as possible from each dyad improvement effort, and then imbed the MPC thinking, processes, and systems int modular approaches to whatever extent possible. That is, one should work hardest with smart partners where new chain benefits are achived, but then try to leverage the learning in other dyads."

(Manufacturing Planning and Control For Supply Chain Management, T. E. Vollmann, page# 665)

Flexible Systems

Leading-edge firms are coming to understand requirements for volume and product flexibility. Some have had experience in repetitive manufacturing applications of JIT and are moving into nonrepetitive applications. An example is a telecommunications equipment manufacturer, which began JIT in its high volume telephone handset operations. The firm had a limited number of high-selling models; in two years its inventory turns were tripled, work in process was reduced by 75 percent, failure rates in manufacturing were cut in half, and setup times fell 50 percent. Thereafter, the firm turned to its low-volume telecom systems plant, where more than 150 basic circuit boards were manufactured, and every end item was somewhat of a custom order. The company learned it needed to go back to the basics of JIT - product engineering, process engineering, and the whole person concept - to successfully implement JIT for its nonrepetitive products.

The firm developed cellular designs, began cellular manufacturing with freat flexibility, and cross trained people with an emphasis on being able to handle volume surges in the telecom systems plant. MRP was still used for overall planning, but far fewer transactions were processed by the hidden factory of indirect labor. In the first six months, first pass yields improved 27 percent, work in process fell 31 percent, and manufacturing cells under JIT hit 100 percent of schedule. The people then helped out other parts of the company that were behinde schedule.

(Manufacturing Planning and Control For Supply Chain Management, T. E. Vollmann, pages321-322)