• Choose a category
• All
• Classic-Fiction

By Root 2813 0

the load on the CCR and determine good safe dates. In a world where the data is frequently not accurate (processing times being, many times, just gross assessments) and being exposed to significant uncertainty from both external and internal sources, the only way to manage well is to look for “good enough” planning and execution rules. The time buffers introduced are usually not optimal, but as long as they are good enough, they do the job. A large order takes more processing time, but that time is usually small relative to the wait time, so as long as we do not speak of an ultra-large order, then probably the same production buffer should be used. In a case where an order, whose size is four times the regular size, is dealt with, then it seems reasonable that such an order has a higher chance of penetrating the red. If this occurrence is persistent, then we might introduce an increase to the production buffer when the specific order size is that much higher than the average order size. The same goes for considering the planned load. As it is not a real schedule and there is no guarantee that the CCR will process the order at the “scheduled” time, it is enough to assert that the given safe date is good enough and let BM take the lead by establishing the required priorities. What else do we need to ensure? We need to release the order at such time that it’ll have a full production buffer time to go through the whole shop, including the CCR.

Thus, the release time of the order should be according to the planned load minus half of the production buffer for that type of order.16 When the safe dates are given to the clients, then the order gets a full production buffer time to cover operations from the material release until order completion.

This rule applies for the vast majority of the cases. Of course, when the CCR is located at the very end of the routing (a very rare case17 in reality), then we adjust the material release and shipping buffer points by shifting the production buffer upstream by adding to the planned load end point just 20 percent of the production buffer to determine the shipping point. The same adjustment is used when a CCR is at the start of the routing. We release the material at least 20 percent of the production time buffer ahead of the planned load, and add 80 percent of the production time buffer to the planned load to determine the safe date for shipment. Only these extreme cases warrant deviation from the rule.

What Happens When Sales Quotes a Different Due Date Than the Safe Date Given by the Planned Load?

The recommended action is for Sales to quote the standard lead time whenever the safe date is prior to the standard. The problem exists when Sales does not follow the safe-date directive and quotes an earlier date than the safe date. If this case is a rare occurrence and most orders are quoted at safe date or later, then our recommendation is to release the manufacturing order to production one buffer time (production buffer) before the due date. If this practice of quoting due dates earlier than the safe dates is not a rare case, then it is not possible to use the safe-date mechanism at all and the company must revert to the behavior of “we do our best to meet the dates, but sometimes we simply are not able to.”

Suppose the safe date is much earlier than the actual shipping date given to the client. Should the release date still be planned load minus half the production buffer? In this case, the actual time buffer is much longer than the production buffer.

The first impulse is to release the order one production buffer time prior to the committed due date. There is, however, one important reason why we should keep the release of the materials at the date the CCR is supposed to process it minus half the production buffer. If we do not release the order at that time, because it is more than the production buffer time until the due date, there is high probability that the CCR would be idle at that time or a little after that. One might argue that having the CCR idle, when it is not an active