Product Interchangeability in Supply Network Planning

In Supply Network Planning (SNP), heuristic-based planning and optimization-based planning both take into account the interchangeability of products. You can use product interchangeability in the Supply Network Planning run to transfer demands for a product that is to be discontinued onto a successor product for instance, or to use existing stock of a current product to fulfill demand for the successor product.

SNP supports the following product interchangeability methods:

Product discontinuation

Supersession chain

SNP supports several supersession chain types. However, cyclic chains, in which a product returns to the chain after having been substituted with another product, are only supported by the SNP optimizer and not by the SNP heuristic. For example:

Chain Type	SNP Heuristic	SNP Optimizer
A->B<->C	X	X
A<->B<->C	X	X
A->B->A (for promotions, for example)	-	X
A->B->C->D->A->B->C->D (when products are changed on a seasonal basis, for example)	-	X

The arrows here indicate the direction of interchangeability for the products. Products can be forward interchangeable (->) or fully interchangeable (<->).

Form-fit-function (FFF) class

For more information about these types of product interchangeability, see the Supersession Chain and Form-Fit-Function Class (FFF Class) sections in the cross-application documentation about product interchangeability in SAP APO.

You have to use the standard SNP planning book called 9ASNP_PS with data view PROD_SUBST to be able to take product interchangeability into account in Supply Network Planning. This planning book contains the required key figures Substitution Demand and Substitution Receipt, and an adapted macro (that takes these key figures into account) for calculating the stock balance. However, you can also create your own planning book based on this standard planning book.

Integration

Product interchangeability in SNP is a fully integrated part of the entire SAP APO product interchangeability process. For more information about this process, see the product interchangeability documentation in Product Interchangeability for instance.
The SNP planned orders and stock transfers generated during planning are transferred to a connected SAP ERP system. However, the SNP product substitution orders that are also generated and linked to these orders are not transferred, with the result that the product substitution data is not visible in the SAP ERP system during Supply Network Planning. However, SNP product substitution data can also be integrated with SAP ERP using Production Planning and Detailed Scheduling (PP/DS). For more information about this, see R/3 Integration of Planned Orders with Interchangeable Components.
Product substitutions for distribution demands cannot be transferred to the SAP ERP system. Therefore, product interchangeability should not be used for distribution demands.

Prerequisites

You have activated product interchangeability in SNP Customizing, Maintain Global SNP Settings (the SNP: Deact. InC indicator).
You have created the master data for running the SNP heuristic or the SNP optimizer and have made the required settings for these planning runs. For more information, see Running the Heuristic in the Background or Running the Optimizer in the Background.
You have defined the product substitution data in the master data for product interchangeability; that is, you have created an interchangeability group (choose Master Data Maintain Interchangeability Group) and have assigned this group to your model (choose Master Data Assign Interchangeability Group to a Model ). Note the following:
- You can choose Supersession Chain or FFF Class as the interchangeability group type for SNP (product discontinuation is created as a supersession chain with only one discontinuation step). SNP does not support group type Restricted interchangeability for FFF classes. Nor does it support rules.
- The interchangeability group always has to be created at the location where there is existing demand.
For more information about maintaining master data, see the following product interchangeability documentation: Supersession Chain, Creating an Interchangeability Group, Form-Fit-Function Class (FFF Class), and Creating FFF Subsets.
If you want to run product interchangeability in the background, you have set the Add products from supersession chains in the functions that you use to run the heuristic or the optimizer in the background. All products of a supersession chain are then included in the selection and planned.
If you do not select this checkbox, the system does transfer the demand to a successor product by creating product substitution orders, but it does not plan the receipt for the successor product. Note that this type of planning does not provide correct results for the entire supply chain, since the system does not plan all products in the supersession chain.

Features

Product Interchangeability Methods

The different types of product interchangeability in SNP are described below:

Discontinuation of Products (A->B)
A product (A) is superseded by a successor product (B) on a specific date. During the planning run, all demands that exist for this product are transferred to the successor product from this date onwards (defined as the Valid-from Date in the product interchangeability master data). You can specify that you first want to use up existing stock of product A by selecting the Use-Up checkbox for this product in the product interchangeability master data. You can also specify a date by which the stock of A has to be used up.

If the system detects demand for A during the planning run and determines that A is no longer valid, it creates a receipt (SNP product substitution order) for A in the Substitution Receipt key figure to compensate for the demand for A. The system also creates a demand for B in the Substitution Demand key figure to transfer the demand onto B. Demand for B is then fulfilled as usual during the planning run (by creating an SNP planned order in the Production (Planned) key figure, for instance). If you have selected the Use-Up checkbox for A, any remaining stock of A is used to fulfill demand for A, even after the discontinuation date, until the stock is used up or until the specified use-up date is reached.
Supersession Chain (A->B<->C, for instance)
A product (A) is superseded by a successor product (B) on a specific date. During the planning run, the system transfers demands for A to B from this date onwards. However, demands for B cannot be transferred to A since A was assigned the interchangeability direction Forward interchangeable. Product B is then to be superseded by product C at a later date. Demands for B will be transferred to C from this date onwards. Since the direction of interchangeability Fully interchangeable was defined for B, requirements for C can also be covered by surplus warehouse stock for B.

To replace A with B, the system proceeds as described in the Discontinuation of Products section above. If the system detects that there is demand for B and that B is no longer valid, it creates a substitution receipt for B to compensate for the demand for B and a substitution demand for C to transfer the demand onto C. If the system detects demand for C and had determined beforehand that there was still surplus stock of B, it creates a substitution receipt for C and a substitution demand for B. Until the use-up date, the system uses the surplus stock of B for covering demand B first. Only if stock of B is still available afterwards does the system also cover demand of C.

Note

By default, first of all, the stock of a product is used to cover the demands for that product. Only after that is it used to cover the demands for the other products in the supersession chain. However, you can use BAdI SAPAPO/SNP_INC_STFW to define that the system is to first pass on the stock to any possible valid subsequent products in the supersession chain before covering the demands for that particular product.

In the case of supersession chains with full interchangeability such as A<->B<->C, C can also be replaced directly by A, for example.

End of the note.
Form-Fit-Function Class (FFF Class)
Different products with almost identical technical properties are grouped into FFF classes and FFF subsets (on a location-specific basis). It is only possible to procure the product that is labeled as the leading product of the FFF subset. In SNP, all demands that exist for the other products of the FFF subset are transferred onto the leading product. If there is insufficient stock of the leading product, stock is used of the other products from the FFF subset. The leading product will be procured (that is, produced in-house or procured externally) only if none of the products have sufficient stock.

If the system detects demand for any product other than the leading product and there is insufficient stock of this product, it creates a substitution receipt for this product to compensate for the demand and a substitution demand for the leading product to transfer the demand onto this leading product.

The system always tries to take into account the stock situation of the products in the FFF subset. Demands are not necessarily covered by the leading product. They can also be covered by products in the FFF subset.

Interchangeability with the SNP Optimizer

In addition to the details given above, the following information applies specifically to interchangeability with the SNP optimizer.

The optimizer's decisions are based on the costs defined for the supply chain model (storage, transportation, production, and procurement costs). It always finds the most cost-effective solution.
The optimizer does not calculate costs for interchanging products at the same location.
In contrast to the heuristic, the optimizer does not consider the product in one location only, but in all locations of the model.

The following example shows the effect of this on product interchangeability:

Example Example

Product A is to be superseded by product B in location C. There is no remaining stock of product A at location C. If demand is received for product A, the heuristic would transfer the demand to product B. However, the optimizer checks whether there is any stock of product A in other locations of the model. For instance, if there is still sufficient stock at location D, the optimizer checks the costs for transferring the stock of product A from location D to location C. If this is the most cost-effective solution (because storage costs at D are higher than the costs for transporting to C, for example), the optimizer plans the stock transfer from D to C. The demand for product A is then covered by the transferred stock.

End of the example.

In the SNP optimizer profile, you can define separately whether supersession chains and FFF classes are to be taken into account by the optimizer. For more information, see Optimization Profiles.

Further Processing of Orders in Deployment

The deployment within SNP can take into account the SNP product substitution orders created by SNP planning and can create deployment orders or SNP product substitution orders in the destination location. For more information, see Product Interchangeability in Deployment.

Activities

Execute an SNP heuristic or optimization run in the background for the products to be planned. Use standard planning book 9ASNP_PS with data view PROD_SUBST or your own planning book that you based on the standard planning book. You can only use the location heuristic for the heuristic run. The network heuristic is not available. If you select the Add products from supersession chains checkbox (see above), you only have to select one product from the interchangeability group and the other products will be included in planning automatically.

If you run the location heuristic or the optimizer in interactive planning, the system also plans all products of the supersession chain automatically in the correct sequence.

For more information, see Running the Heuristic in the Background and Running the Optimizer in the Background.
The system takes into account the product substitution data that has been defined for product interchangeability in the master data and, alongside SNP planned orders and stock transfers, creates SNP product substitution orders in the Substitution Demand and Substitution Receipt key figures if required.
View the results in interactive Supply Network Planning. The following display options are available for product interchangeability in addition to the usual display options:
- Shuffler: You can choose the Product Interchangeability Group characteristic in the shuffler and display all the location products, products, or locations for a particular interchangeability group.
- The Display dependent objects function: You can use this function to display the demands for predecessor or successor products, for instance.
- In the Stock on Hand key figure, stock of a product that is no longer valid and may no longer be used is highlighted in color.
- The predecessor and successor products are displayed in the detail view. The product you selected in the selection area for planning or displaying data is highlighted in color.