Forecasting with Bills of Material 
Purpose
You can forecast dependent requirements in Demand Planning. The system determines the component parts of finished products through the production process model (PPM).
This can be useful if material components represent practical constraints on the forecast at finished product level; that is, the available quantity of components is fixed but they can be used in different finished products. This situation arises in, for example, the chemical industry. The planner can immediately see the impact of the product forecast on the fixed component level.
This process can also be used in the consumer products industry to model a store display consisting of multiple products from one vendor. Both the display (the finished product) and the individual products (planned in Demand Planning as components) are released to Supply Network Planning.
In other industries, such as automotive part suppliers, actual demand occurs only at the component level while the finished product (for example, the car) has the role of making the part suppliers' forecast more transparent (for example, if one cassette box is built into each car, and it is known that 1000 cars will be manufactured, then the supplier's demand forecast for cassette boxes is also 1000). Demand for the finished product is not released to Supply Network Planning. The DP PPM allows you to model this situation.
Process Flow
You create and activate a PPM for Demand Planning manually. (You create a PPM for Supply Network Plannng either manually or by converting a PP/DS PPM that was transferred from R/3 into an SNP PPM.)
SAP recommends that for this process you use single-level PPMs; that is, PPMs where all components for the finished product have been entered as inputs on the same level. This usually requires some prior calculations of input-output quantities.
This adds the characteristics 9AMATNR and 9APPMNAME to the master planning object structure. You can add any other characteristics that are required.
The field for the characteristic PPM is grayed out. The PPM information is not generated in this step.
This step generates additional characteristic value combinations for material components as entered in the BOMs.
In some industries, you may wish to release material component demand to SNP instead of finished product demand; this is the case where the components are the products for which actual demand will occur (see
In cases where a product has both independent and dependent demand (such as consumer goods that can also form part of a store display), you can use a macro to sum the two demand types before releasing to Supply Network Planning.