Planning Heuristics in Repetitive
Manufacturing (REM Heuristics)
Use
Heuristics are provided to solve specific problems within the area of production planning and detailed scheduling.
For planning production in repetitive manufacturing, SAP provides two basic heuristics (REM heuristics; REM = Repetitive Manufacturing). You can change the settings for these heuristics in Customizing, or use them as a template for programming heuristics with your own algorithm (see Setting Up REM Heuristics Creating REM Heuristics with your own Algorithm ).
The SAP standard REM heuristics are particularly suitable for planning non-configurable products that are to be produced on simply structured lines (such as filling lines). With these heuristics you can plan several resources (in repetitive manufacturing with PPM) or lines (in REM with iPPE: resources of type line) simultaneously. In this way you can produce products on alternative resources (lines), and load them as you wish within finite planning.
For planning configurable
products, a special planning run is available within model mix planning
with a special heuristic. For further information see
Model Mix Planning
Run.
Integration
You can use the REM heuristics the following scenarios:
·
Repetitive
Manufacturing with the Production Process Model (PPM).
·
Repetitive
Manufacturing with Integrated Product & Process Engineering (iPPE)
The heuristics can be used both in interactive planning and background planning.
Prerequisites
· The products that you want to plan are not configurable.
· The structure of your repetitive manufacturing is very simple with only one operation per resource. If there are several operations per resource, the system takes the last operation as the basis for scheduling.
Complex iPPE line networks cannot be planned with these REM heuristics. With line networks that consist of several lines, the system always plans the last line.
· The products that you want to plan within a planning run with a specific REM heuristic are on the same low-level code and you plan the bill of material structure sequentially from top to bottom.
You cannot plan final products and dependent assemblies at the same time. If you plan the finished products, the dependent requirements for the assemblies can only be taken into account in a subsequent heuristic run.
· You have maintained the necessary master data.
Features
The following REM heuristics are contained in the SAP scope of delivery:
· Heuristic for Multi-Resource Planning (Even) (SAP_REM_001).
In this heuristic, the resources are loaded as evenly as possible.
· Heuristic for Multi-Resource Planning (Primary Resource) (SAP_REM_002).
In this heuristic, resources that are defined as preferred resources are loaded first of all. Planned orders are not moved to the alternative resources until these resources are at full capacity.
Both SAP REM heuristics initially carry out the net requirements calculation, then calculate the lot sizes according to the settings in the product master and finally create scheduled APO planned orders for the available requirements, taking into account the free resource capacity available per period. Depending on your settings, the periods could be daily, weekly, or monthly. User-defined time periods are also possible.
To determine the requirement quantities and dates for the necessary components, the REM heuristics then carry out a single-level individual explosion of the iPPE data, or the production process model and thus determine the dependent requirements for the BOM level directly below.
The heuristics only work with firm setup times and do not take into account sequence-dependent setup, as defined in the setup matrix of the production process model.
Activities
You can start the planning run with REM heuristics in the following applications:
·
In the product planning table: Select the
resource you want to plan, display the view Heuristics (or choose
Variable
heuristic, or in the menu Planning
→
Heuristic),
select the heuristic you want, make any other settings for the heuristic and
start the planning run.
· In the product planning run: Enter the resources (lines) that are to be planned and the products in the propagation range, enter the heuristic and select resources as objects that have still to be planned. Save your entries in a variant, and schedule the variant to meet your requirements. The planning run is then automatically started as a regular background job.
· In other applications of interactive planning (detailed scheduling planning board, product view).