The engineering and design department may specify that a material is to be replaced by another at a particular point in time.
Replacing a material by another may be necessary in the following situations:
- If a component no longer meets safety requirements, new safety regulations may require replacing the component after a certain point in time.
- A cost-intensive part may be replaced by a less expensive one.
Discontinuation control works for long-term master production and requirements planning in the same way.
Discontinuation control is of the following types:
- Simple discontinuation
- Parallel discontinuation
In parallel discontinuation, one group of materials is replaced by another. Therefore, when one (main) component is discontinued and its available stock is zero, another (dependent) component must also be discontinued. For example, if a particular nut is discontinued, the corresponding screw is also discontinued.
The prerequisites for parallel discontinuation are as follows:
- In the material master record of the main discontinued component, set the Discontinued field to 1. In the Follow-up field, 3 appears in the material master record of the dependent discontinued component.
- In the extras for the BOM item, define a discontinuation group under Follow-up/Discontinued dates. This freely definable character string contains a summary of the associated and discontinued items of a BOM. You can identify the main component to be discontinued (along with its dependent component) using the same discontinuation group.
Note
You can also define the follow-up component(s) using the Follow-up field. The successor group contains a summary of the associated follow-up items in a BOM. This successor group determines which follow-up items replace the discontinued items. The character string of the successor group must correspond to the character string of the discontinued group.Alternative Items
An alternative item group serves to summarize alternative items within an item list. All assembly materials can be entered in the alternative item group. As soon as you create an alternative item group, an additional dialog box containing the ranking order, strategy, and probability of usage appears.
You can maintain alternative items in the following situations:
- Alternative items with specified usage probability:
These alternative items incorporate a certain usage probability. Create a usage probability for each alternative item in a group, so that in requirements planning a dependent requirement is created and is changed to a reservation in the production order.
- Alternative items as information:
You can also create an alternative item for information purposes. For instance, information is only referenced in missing part situations. As neither a dependent requirement nor a reservation will occur for this item, you do not produce a usage probability.
Backflush
Backflush occurs according to the following usage probabilities:
- Backflush according to usage probability:
For all items that you want to reserve, specify the following:
- Strategy (value 1 or no entry)
- Ranking order (only affects the sorting of materials)
- Usage probability
- Backflush at 100% availability:
For all items that you want to reserve, specify the following:
- Ranking order
If you do not specify a ranking order, the system checks the items in the order in which they are transferred for the availability check (value 1 or no entry).
- Strategy (value 2)
- Usage probability
Backflush at 100% availability (strategy 2):
With this strategy, the availability check is executed in the specified ranking order according to ATP logic
- Ranking order
The following is an example of some backflush usage probabilities:
Gross requirements: 100 pieces
Backflush Usage Probabilities
| Material | Usage Probability | Ranking | Planned Requirement Amount | ATP Quantity | Backflush Quantity |
|---|---|---|---|---|---|
| A | 20 | 1 | 20 | 30 | 0 |
| B | 30 | 2 | 30 | 150 | 100 |
| C | 50 | 3 | 50 | 180 | 0 |
In the example, the alternative items are determined as follows:
- The first material in the ranking order (that meets the requirement date 100%) is reserved in the required quantity (material B).
- Once a partial backflush has occurred for a production order, no further check takes place for more partial backflushes with this production order. Future partial backflushes, if any, take place from the alternative item from which the first backflush occurred.
- If (with strategy 2) none of the alternative items meet the requirements 100%, the availability check confirms each available quantity. A reservation is then made for the available quantity.