Alternative Items in an Alternative Item Group

An alternative item group is used to group together alternative items in a BOM. Any of the materials in the alternative item group could be included in the assembly. These items are known as alternative items in the BOM.

You can use alternative items in the following situations:

• Alternative items with a usage probability

The alternative items are included with a certain usage probability.

• Material requirements planning (MRP) uses the usage probability to determine dependent requirements for the materials.
• In the production order, dependent requirements are converted to a reservation.

The withdrawal posting for the reservation in the production order uses either the usage probability or the 100% availability check according to ATP logic.

• Alternative items for information

You can enter an alternative item for information only. For example, the item is only relevant to missing parts. The usage probability for the item is 0%.

Data for Alternative Items

Use

When you enter an alternative item group for the item, you can enter the Priority , Strategy, and Usage Probability in a dialog box.

Features

Usage Probability

Material requirements planning (MRP) plans the alternative items according to usage probability.

If you use the usage probability to determine the withdrawal posting (strategy 1), the quantities are proposed according to the usage probability. You can change the proposed quantities.

• An alternative item is only planned if the usage probability is at least 1%.
• If the usage probability is 0%, a dependent requirement with quantity 0 is generated for the material.

The component with the quantity 0 is displayed in the planned order. If required you can increase the quantity there.

• It is possible to plan too much for alternative items, because you can enter usage probabilities that add up to more than 100%.

Priority

The priority of an item within an alternative item group determines the sequence in which material components are reserved in the production order.

Strategy

The strategy is only relevant to the withdrawal posting in the production order. The strategy is ignored in MRP.

You use the strategy to determine how the items within an alternative item group are selected for the withdrawal posting. Use the same strategy for all alternative items in an alternative item group.

The following strategies for withdrawal postings are supported:

• Withdrawal according to usage probability (manual changes possible)
• Withdrawal if availability is 100%

Strategy: Example

If you use this strategy, the availability checks uses ATP logic according to the priorities you define.

100% Availability

Gross requirements: 100 pieces

Calculating issue quantity for 100% availability

The required quantity of the first material in order of priority that covers 100% of requirements is reserved (material B).

The system sets the usage probability of the reserved material to 100%. The quantity and usage probability of the other alternative items (materials A and C) are set to 0.

Missing Parts Situation

When none of the alternative items cover the requirement 100% on the requirements date, the availability check confirms a 0 quantity for all the items. This means that there is no reservation.