Product Interchangeability in PP/DS

The continued development of products or changes to production processes can make it necessary to discontinue a product and substitute it with a successor product. Production Planning and Detailed Scheduling (PP/DS) supports procurement planning and order processing for interchangeable products, whose substitution relationships are represented by a linear supersession chain. A linear supersession chain is characterized by the fact that different products replace each other, and that exactly one product is valid at each point in time in the supersession chain. A product may only be procured in its validity period using external procurement or in-house production. Substitution rules, which contain conditions for substitutions (restricted product interchangeability), are not relevant for PP/DS.

The task of procurement planning in PP/DS is to use up any existing surplus product stock in the transition period after the discontinuation of a product for product requirements, if this is permitted. Procurement planning also procures the valid successor product to cover requirements that are still open. By planning with product interchangeability (InC), you can therefore reduce scrap. In the execution phase, PP/DS has to react to short-term date/time and quantity changes and to update the components from an in-house production order, while taking the supersession chain into consideration.

PP/DS also always plans in an integrated scenario with an SAP R/3 system on the basis of product interchangeability master data you have created in SAP APO. Therefore, you plan an interchangeable component either in SAP APO based on the product interchangeability master data in SAP APO, or in SAP R/3 based on the discontinuation data in SAP R/3. (You can, however, transfer discontinuation data from SAP R/3 to SAP APO.) A scenario in which you take account of discontinuation data for an interchangeable component in both systems does not make sense.

PP/DS supports product interchangeability in in-house production scenarios. This documentation describes in-house production scenarios in which you plan assemblies and their interchangeable components in SAP APO. These include the following scenarios:

Shop Floor Production or Repetitive Manufacturing with Order Processing in SAP R/3
In this scenario, you plan shop floor production or repetitive manufacturing in SAP APO based on production process models (PPMs) or PP/DS runtime objects. You implement SAP APO in connection with an SAP R/3 system for order processing. The prerequisite for processing manufacturing orders is release SAP R/3 4.0B or a higher release. In this scenario, you can plan product interchangeability at finished product level and component level. For more information, see Product Interchangeability with Order Processing in SAP R/3.
Repetitive Manufacturing with Production Backflush in SAP APO
In this scenario, you plan repetitive manufacturing in SAP APO based on master data for Integrated Product and Process Engineering (iPPE). You implement SAP APO in connection with a DI system with the release SAP R/3 4.6B or higher. In this scenario, you can only plan product interchangeability at the level of the components that cannot be configured. You cannot plan product interchangeability at the level of configurable finished products. For more information, see Product Interchangeability in REM with Production Backflush in SAP APO.

PP/DS also supports product interchangeability for project orders. For more information, see Copying Substitute Components in the Project Order.

Integration

The usage of product interchangeability master data is integrated in the following applications:

Planning in the MRP run and with the product heuristic
To avoid unnecessarily large surplus stock arising for a discontinued product, or requirements not being covered, procurement planning for an interchangeable product can never be executed independently of the other products in the supersession chain. If you want the system to execute procurement planning in the MRP planning run or in planning with the product heuristic for an interchangeable product, it automatically plans all products in the supersession chain. To map the substitution of a product by another product, PP/DS creates a product substitution order in procurement planning. During the planning phase, substitution information for a component in a planned order is only contained in this product substitution order. The bill of material (BOM) of the planned order is not changed. Since you cannot transfer product substitution orders to SAP R/3, product substitutions are not visible in this phase in SAP R/3. For more information, see MRP Run for a Supersession Chain.
Setting the conversion indicator and ATP check for in-house production orders in PP/DS
To take the limited time validity of order components into account at the start of the execution phase by the latest, and to adopt substitute components in a planned order, if required, you have to set the conversion indicator in PP/DS or perform a suitable configured ATP check. This is dependent on the scenario. After the planned or manufacturing order is transferred to SAP R/3, the substitution is also visible there.

If the system explodes the plan for the source of supply when an in-house production order is created or changed, the system does not take account of product interchangeability. The system uses the components that exist in the plan for the source of supply (and that may already be discontinued by the requirements time).

Note Note

Note that the PP/DS function for planning with product interchangeability is used to support planning in the transition period when a product is switched. The function does not replace a regular, timely update of BOMs in PPM plans, iPPE process structures, and PP/DS runtime objects.

End of the note.

Prerequisites

The supersession chain must fulfill the prerequisites described under Supersession Chains for PP/DS.

The following table contains an overview of special prerequisites and constraints for planning product interchangeability in different scenarios and PP/DS functions.

Function, Scenario	Constraints and Prerequisites
Manufacturer part number management	Manufacturer part number management is not supported.
Complex product interchangeability	Complex product interchangeability is not supported. This includes substitutions of the form 1:N, N:1, N:M and restricted product interchangeability.
External procurement	Subcontracting and collaboration using scheduling agreements (CMDS) do not take product interchangeability into consideration. For stock transfer scenarios, you have to consider specific prerequisites.
Configuration	Planning product interchangeability based on configurable products is not supported. Configurable products cannot be part of a supersession chain.
Heuristics	Only specific procurement planning heuristics are suitable as product heuristics, such as the standard heuristic SAP_PP_002 for planning standard lots. For example, the following heuristics do not take account of product interchangeability: Procurement planning heuristics that plan products according to a reorder point method Heuristics for planning continuous requirements, such as the standard heuristic SAP_PP_C001 for Planning standard lots for conti-I/O. Standard heuristics for repetitive manufacturing: SAP_REM_001 and SAP_REM_002 Standard heuristic for model mix planning
PP/DS functions that define or change dates/times	Functions such as Detailed Scheduling (DS), DS heuristics, or optimization do not take account of the limited time validity of the products in a supersession chain when scheduling or rescheduling an order. Therefore, an order can be scheduled or rescheduled so that the requirements date/time of a dependent requirement for an interchangeable product is outside the validity period of the component.
Parallel discontinuation	PP/DS does not support parallel discontinuation, in which several products are discontinued simultaneously. You can only plan parallel discontinuation in SAP R/3.
Multiple substitution for integration with SAP R/3	You cannot transfer in-house production orders with a multiple substitution to SAP R/3. For you to be able to transfer an in-house production order to SAP R/3, the order, in addition to the original item, can contain a maximum of one substitute item. For more information, see Product Interchangeability with Order Processing in SAP R/3.
Capable-to-Promise scenario (CTP)	You cannot plan with product interchangeability in the CTP scenario. CTP uses the planning procedure Cover dependent requirements immediately, which reacts to changed dependent and stock transfer requirements with the action Cover Dep./Stk Tr. Requirement Immediately and plans the components immediately. This action cannot take product interchangeability into consideration. The heuristic SAP_PP_003 for Planning shortage quantities does not take account of product interchangeability either.
Planning with shelf life data	Planning with shelf life data is only possible with the following prerequisites and constraints: The shelf life data must be the same for all products in a supersession chain. The system does not take shelf life data from the sales order into consideration when requirements are being forwarded to a successor product. The system uses the shelf life data from the product master for the successor product. In requirements forwarding, the system takes the maturation time into consideration, both for the predecessor and the successor product. Therefore, there is a time period between the requirements date/time for the predecessor product and the availability date/time for the successor product, which includes the maturation times of both the predecessor and the successor. The maturation time of the successor product is thus in the past by the requirements date/time. If you want to plan using the maturation time, you should not plan with product interchangeability.

Note Note

You should refer to the scenario documentation for planning with product interchangeability for additional more specific constraints.

End of the note.

More Information

For information on planning interchangeable components in SAP R/3, see the SAP R/3 documentation for Discontinuation Data, for example.