You can determine in engineering/design that a material is to be replaced by another one at a certain point in time. When replacing a component with another, however, the stock of the old material should be used up before the new one is introduced in order to avoid dead stock.

It may be necessary to replace one part for another if:

• one part is replaced by a more technically advanced part
• an expensive part is replaced by a less expensive part

The task of MRP when discontinuing parts is to reassign the dependent requirements for the component to be discontinued to the follow-up material, once the stock of the part to be discontinued has completely been used up.

The system differentiates whether

• exactly one material is to be replaced by one follow-up material (simple discontinuation), or
• a group of materials is to be replaced by another group of materials (parallel discontinuation).

• You have entered the following data in the material master (MRP 4 view) for the material to be discontinued (in parallel discontinuation: for the main material to be discontinued):

• Indicator 1 for Single/parallel discontinued part/material
• Follow-up material
• Effective-out date

• In parallel discontinuation, you have defined the link between the parts to be discontinued and the follow-up material in the BOM:

• All parts to be discontinued and all follow-up materials have been entered in the BOM.
• Parallel discontinued parts have the same discontinuation group. You enter these in the BOM item.
• The follow-up parts are set to the follow-up group. You also enter these in the BOM item. The follow-up group key is set correctly with respect to the discontinuation group.

You can find further information on this in the SAP document PP – Bills of Material.

During the planning run, the system checks the discontinuation indicator and the effective-out date in the material master and reassigns the materials correspondingly. The system reassigns the requirements during the planning run for the discontinued material and not during the BOM explosion. The system reassigns only dependent requirements and dependent reservations.

Starting from the effective-out date, no new procurement proposals are created for the material to be discontinued. Once all the stocks of this material have been used up, its dependent requirements are reassigned to the follow-up material. If there is still enough stock of the material to be discontinued to cover a part of the dependent requirements, this stock is used and the rest quantity is reassigned to the follow-up material.

In parallel discontinuation, you use the indicators in the material master and the link in the BOM to instruct the system to discontinue all materials in the group when the stocks of the main material to be discontinued have been used up. How the dependent parts react depends completely on the stock of the main material to be discontinued. These dependent parts are replaced once the stocks of the main material to be discontinued have all been used up. The dependent requirements are then reassigned to the follow-up materials.

Additional requirements created after the effective-out date are not reassigned and no new procurement proposals are created for them. The system sets the Uncovered requirement after effective-out date exception message. This applies to the following requirement types:

• Manual reservations
• Independent requirements and forecast requirements
• Sales orders
• Requirements for subcontracting

The safety stock is not used up after the effective-out date because safety stock should also be maintained after then to cover unplanned requirements such as a requirement for a replacement part.

The system therefore reassigns the dependent requirements to the follow-up material even if safety stock is available. If the stock level drops below the safety stock, the system also creates a procurement proposal for the discontinued material after the effective-out date. The system issues the Receipt after effective-out date exception message for the procurement proposals.

When discontinuing parts, the system does not include fixed receipts such as order proposals or production orders if they are after the effective-out date. The system issues the Please cancel and Receipt after effective-out date exception messages.