Additional Factors that Affect Search Strategies - SAP WM

There are several ways that the putaway and picking strategies can be influenced, for example by:

  • Storage types
  • Storage sections
  • Storage bin type
  • Cross-line stock putaway
  • Capacity check

You create and maintain these objects using the Customizing application. For more information, see the Strategies section of the Warehouse Management section in the Implementation Guide (IMG). For each of the first three options, the system lists additional objects that you need to maintain and the order in which they should be maintained.

Cross-Line Stock Putaway
Use
In this function, a sort variable helps the system to search for suitable storage bins. With the sort variable, you can eliminate the problems caused by one-sided loading in the warehouse and optimize the stock putaway process in your warehouse. If the sort variable has not been defined, the system sorts using the storage bin coordinate itself.

Integration
With the putaway strategies L (next storage bin) and P (storage unit type), you can influence the search for a suitable storage bin with the help of a sort variable. This method can also be set up for storage types with putaway strategies L (Addition to existing stock) or B (Bulk storage), since if the system does not find a bin for adding to existing stock, it will use sort variables to find an empty storage bin.

Prerequisites
You define the sort variable for cross-line stock putaway in Customizing for Warehouse Management. For further information, refer to the Implementation Guide (IMG) for Warehouse Management under the section Strategies.

For each storage type, you can use up to six fields of the storage bin coordinate to define the sort variable. You determine which positions of the coordinate are relevant for the variable structure and in which sequence the individual positions are used in the variable.

For example, storage type 001 has

  • Coordinate positions 1 2 3 4 5 6 7 8 9 10
  • Coordinate structure R R - S S - L L *
  • Variable structure S S - L L
* R = row S = stack L = level

The fourth and fifth positions of the coordinate, which represent the two digits of the stack, make up the first two positions of the variable. The seventh and eighth positions of the coordinate, which represent the two digits of the level, make up the last two positions of the variable. To define the sort variable, enter the numbers 1, 2, 3, 4, and 5, as shown below, in the data entry table. Start at the fourth position.

Positions in bin coordinate ------

Positions in bin coordinate

When the system looks for an empty bin with the new structure, the first storage bin it finds is 01- 01-01. However, the next time it looks for an empty bin, the next coordinate it finds is 02-01-01, which represents the first stack in the second row. This process continues until all stacks in all rows are filled for the storage type. You must define the sort variable before you create the storage bins. Any subsequent changes to the table affect only newly created storage bins.

Example
In the examples below we use the "next empty bin" strategy to explain the concept of cross-line searching.

cross-line searching

The view shown in the figure is a top view looking down on the warehouse. To make things simpler, we assume that the warehouse consists of one level.

Searching for Bins Without a Sort Variable
When searching for empty storage bins without using a sort variable, the system makes its search based on the following structure:

Searching for Bins Without a Sort Variable

With this structure, the system fills the warehouse row by row. For example, the system fills the first row completely first, then the second row, then the third. This can result in a one-sided load of the warehouse.

Searching for Bins with a Sort Variable
When you define a sort variable, empty storage bins are sorted differently. For example, you transfer goods first to stack 01, level 01 in row 01, then to stack 01, level 01 in row 02, then to stack 01, level 01 in row 03, and so on. In this case, you define the sort variable as follows, where R is the row, S is the stack and L is the level:

  • Storage bin: RR – SS - LL
  • Variable: SS - LL

With the sort variable, empty storage bins have the following structure.

Searching for Bins with a Sort Variable

With this structure, the system fills the bins in the warehouse on a stack-by-stack basis for each row. When the system selects bins for stock received in the warehouse, the first stack in each row is filled, then the second stack in each row, then the third stack, and so on.

Capacity Checking
Use
For some putaway strategies, it is advantageous to require that the system check the capacity of the storage bin when it searches for an available bin. If the capacity check is active, it means that during the process of transfer order creation, the system checks whether the storage bin you selected has the capacity to store the quantity that is to be put away.

Prerequisites
You can implement capacity checking on the basis of a storage type when you define the putaway strategy or the storage type in the Warehouse Management section of Customizing. For more information about activating the capacity check, refer to the Implementation Guide (IMG) for Warehouse Management under Master Data →Define Storage Type. To activate the capacity check, enter the number that represents the checking method in the Capacity check method field for the putaway strategy in the storage type record.

In order to control the capacity check according to capacity indicators, the following basic prerequisites must be met:

  • Each storage bin must have a capacity that is independent of dimension or unit (simply a number).
  • Each material can use a specific capacity for each unit of measure.
  • Each storage unit type can have a specific capacity for each storage unit.

Features
There are six options available for capacity checking in the Warehouse Management (WM) component. The capacity of a bin can be checked on the basis of:

  • Weight
    The weight of the material that is being transferred to the storage bin is checked against the remaining weight capacity of the bin.
  • Storage unit type
    You can stipulate that the storage bin can contain only one standard storage unit type. This is taken from the first SUT field under Palletization data in the material master record.
  • Maximum quantity for a bin in the storage type
    You can define the maximum quantity of material that can be stored in a bin for each storage type. This is often used for the fixed bin strategy.
  • Capacity indicator (see below)
    - Usage check based on material
    - Usage check based on storage unit type (SUT)
    - Usage check based on material plus SUT

We recommend that you implement a capacity check for the “fixed bin storage” and “addition to existing stock” putaway strategies. For bulk storage, capacity checking is carried out in the block definition.

Capacity check according to capacity indicator
You can also use the capacity indicator to control the storage of materials in a storage bin. Depending on the capacity check you select, the system calculates the capacity usage differently.

  • For the material, the capacity usage is calculated based on the quant (the quantity of a single material with the same characteristics), as in example 1.
  • For SUT checks, the system calculates the capacity usage based on the storage unit type. (Example 2)
  • For mixed storage situations, we recommend using the capacity check that is based on the sum of the material and the storage unit type. In SU-managed storage types, each storage unit counts as a separate SUT; in non-SU-managed storage types, each quant counts as a separate SUT.

Capacity check according to capacity indicator

Since the capacity usage is dependent upon the quantity of the material, it is characterized as a variable in the system and is updated in the quant. The capacity usage of an SUT is characterized as a constant capacity usage and is updated in the storage unit in SU-managed storage types and in the quant in non-SU-managed storage types.

Data from quants and storage units are updated for each storage bin as a remaining capacity. This remaining capacity is recorded in the empty bin index. This makes it possible to efficiently find an occupied storage bin with a specific remaining capacity by using a customer exit, for example.

Capacity Checking Based on a Neutral Indicator
The following examples correspond to the three neutral capacity checks. For these examples. The following conditions apply:

  • The material is managed in the base unit of measure “pieces” and has a capacity usage of 11 per piece.
  • Storage Bin 01-01-01 has a capacity of 100.
  • The storage unit type (SUT) has a capacity usage of 12.
  1. Capacity usage check based on the material
    Nine pieces of the material can be stored in storage bin 01-01-01. This leaves a remaining capacity of 1 as illustrated below. This capacity check is advantageous if you can stack materials as desired into this storage bin. It could also replace capacity checks 2 and 3 if there are different batches that results in mixed storage.
  2. Capacity usage check based on the material

    The capacity checks in points 2 and 3 only function properly when the SUT check and SU management are active in the storage type record.

  3. Capacity usage check based on the storage unit type (SUT)
    Eight full wire baskets can be stored in storage bin 01-01-01. This leaves a remaining capacity of 4. This capacity check is advantageous when the SUTs are next to each other and the materials can be removed one at a time from each container.
  4. Capacity usage check based on the storage unit type (SUT)

  5. Capacity usage check based on the sum of the material and the SUT
    Eight pieces can be stored in storage bin 01-01-01 on an E1 pallet. This leaves no remaining capacity for the bin. This is illustrated in the following graphic:
  6. Capacity usage check based on the sum of the material and the SUT

    If the material is stored in the bin with one piece per E1 pallet, 4 pallets will fit in the bin (44 + 48) and a remaining capacity of 8 exists as shown below. This capacity check is advantageous if the pallets are stacked on top of each other and the thickness of the pallet must be taken into consideration.

    Capacity-Checking-Based-on-a-Neutral

    Before you make the first stock placement, you need to define the type of capacity check and the capacity usage of material and storage unit types. Changes that are made to these parameters afterwards cause automatic changes to storage bins, storage units and quants. If you make changes in the operational system, you must run report RLS10200 to adjust the occupied capacities for bins, storage units and quants.


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