Intended learning outcomes: Describe rescheduling of orders in process according to current materials management status.
Continuation from previous subsection (15.1.3b)
Corma, Part 3: Coupling shop floor control with materials management. To do this, the planner checks the inventory on an ongoing basis and calculates the point in time at which inventory will fall at zero, assuming average use. This point in time becomes the probable date on which the replenishment order should arrive in stock. Clearly, software can provide for easy calculation here. The planners (or software) transfer this date to become the latest completion date for the replenishment order as soon as they consider the difference to the actual latest completion date to be significant. The following situations may arise:
- The latest completion date will be pushed forward, if inventory stock is being depleted at a rate faster than the statistical average for the period up to the point of order release. Rescheduling then calculates a smaller lead-time-stretching factor. This results in higher priority, and the order is accelerated.
- The latest completion date is postponed if inventory stock is being depleted at a rate slower than the statistical average for the period up to the point of order release. Rescheduling generates a higher lead-time-stretching factor. This results in lower priority, and the order is slowed down.
To show the effects of the Corma principle, let us look at a stock replenishment order with three production operations. Figure 15.1.3.3 shows four possible situations.
Fig. 15.1.3.3 Rescheduling of orders in process according to current materials management status.
- First situation: Because of the early order release, all three work operations are evenly distributed between the earliest start date (i.e., the earliest possible start date of the order, which is originally the date of the early release and then moves — in fact — forward along the time axis with the “today” date) and the latest (acceptable) completion date for the order (that is, the order due date). They are all scheduled, but — in this situation — without priority. As a result, they are performed as soon as there are no more urgent operations waiting to be processed at the work station.
- Second situation: The mixed-mode manufacturer accepts an unplanned customer order with a high priority. Then the stock replenishment order in process will wait. Not even the first operation is performed. However, the ongoing rescheduling “discovers” any order that has waited for too long, and the latest start date, that is, “today,” is being pushed closer to the latest completion date. Rescheduling then calculates a smaller lead-time-stretching factor. This gives the order higher priority.
- Third situation: The inventory stocks fall faster than expected. The latest completion date is therefore brought forward. Rescheduling calculates a smaller lead-time-stretching factor, and the order is accelerated by expediting.[note 1506]
- Fourth situation: The inventory stocks fall slower than expected. Thus, the latest completion date is postponed. Rescheduling calculates a higher lead-time-stretching factor, and the order is delayed.
The third and fourth situations in Figure 15.1.3.3 illustrate the most important aspect of the third part of Corma. Stock replenishment orders will receive the same priority as customer production orders if stock falls below safety stock. If the demand is lower than expected, however, stock replenishment orders will not even start, or will be halted. Alterations in the due date of a customer production order may also lead to rescheduling, with consequences similar to those in situations 3 and 4 above.
Continuation in next subsection (15.1.3d).
Course section 15.1: Subsections and their intended learning outcomes
15.1 Order Release
Intended learning outcomes: Describe order proposals for production and procurement as well as order release. Explain load-oriented order release (Loor) and capacity-oriented materials management (Corma).
15.1.1 Order Proposals, Order Release for Procurement and Production
Intended learning outcomes: Describe the reasons for order proposals for production or procurement. Differentiate between the dealing of order proposals for C items and of other items. Explain purchase order release. Explain production order release and describe the availability test of resources.
15.1.1b Production Order Release: Allocation, Staging, Accompanying Documents and Container Logistics
Intended learning outcomes: Disclose issues linked with allocation and staging. Identify accompanying documents such as the traveling card and container logistics such as the two-bin inventory system.
15.1.2 Loor — Load-Oriented Order Release
Intended learning outcomes: Produce an overview on the principle of the technique and the planning strategy. Describe the regulator analogy for load-oriented order release. Differentiate between time filter and load filter.
15.1.2b Load-Oriented Order Release: Example and Evaluation
Intended learning outcomes: Explain the steps of load-oriented order release. Present an evaluation of the technique. Identify its limitations and typical areas of application.
15.1.3 Corma — Capacity-Oriented Materials Management
Intended learning outcomes: Disclose the main objective of mixed-mode manufacturers. Produce an overview on the three parts of the generic principle of the technique.
15.1.3b Corma, Part 1: Criterion for early order release, and Part 2: Scheduling technique for control of operations.
Intended learning outcomes: Identify the calculation of anticipation time in the stochastic case. Explain the critical ratio of an order.
15.1.3c Corma, Part 3: Coupling shop floor control with materials management
Intended learning outcomes: Describe rescheduling of orders in process according to current materials management status
15.1.3d Corma: Example and Evaluation
Intended learning outcomes: Present an example and an evaluation of the technique. Identify its limitations and typical areas of application.
