Reveal SAP EWM

Work center determination for a packing process

This blog reveals the logic for destination bin / work center determination for a packing step as part of an outbound storage process. You might want to think “Yeah – I know – there is this determination table which we can use here”. This is correct, but there is more to it. As usual, I do promise to give you some technical details and toppings that you will not find in any of the SAP books or system help text!

As mentioned above, the scope of this blog is limited to packing steps which are executed in the context of outbound processes. This is mainly because a rules-based determination via the POSC is not possible during the inbound process, which makes it a bit boring ;-).

Sidenote: In order to execute system-supported packing during an outbound process you need to make use of the POSC meaning you have to use a storage process with a packing step:

SAP EWM work center determination for packing_01

Of course you can create HUs also during picking without a packing step but we are focusing here on packing steps which are executed separately from the picking process at dedicated packing work centers.

Agenda
– Options for packing bin / work center determination
– Rules-based vs. non-rules-based determination
– Deep-dive into the different options
– Consideration of the putaway strategy
– Options for enhancements

Options for packing bin / work center determination
In general, we do have three options for the destination bin determination here. We can determine the packing bin / work center
1. based on type/section/bin in the given storage process step
2. based on the corresponding warehouse order creation rule (WOCR)
3. based on the determination table

Rules-based vs. non-rules-based determination

We can separate those three options into rules-based and non-rules-based ones. Option (2) and (3) are rules-based and only relevant in case the corresponding flag is active for the packing step of the given storage process:

SAP EWM work center determination for packing_02

Deep-dive into the different options

Option (1) is the easy one, which is relevant in case the rules-based flag is not active for the given process step. In this case EWM will just read the ‘fixed’ type/section/bin that you provide in the process step customizing:

SAP EWM work center determination for packing_03_2

That is all you need to know for the non-rules-based logic. Let us now have a look at the logic for rules-based work center determination!

In general (there are some exceptions), the ‘Rules-based’ flags will determine the destination which is needed to complete the previous step of the storage process (so e.g. a record with step OB02 will set the destination for step OB01):

SAP EWM work center determination for packing_04

Function module /SCWM/STORAGE_CONTROL_P_GET is the most important player here. It calls the destination bin determination for the different kind of internal steps. For packing steps EWM determines the destination for the previous step (usually a picking step) via FM /SCWM/DET_PACKING_STATION.

This FM first checks whether you gave a fixed destination via the warehouse order creation rule (this is option (2), mentioned above):

SAP EWM work center determination for packing_05
Fun fact – you notice the comment with the ‘bundling rule’ in the screenshot above. Never heard that before as a synonym for a warehouse order creation rule but at least for a business user it is probably a more meaningful/helpful term.
SAP EWM work center determination for packing_06
If it finds something, we are already done here. If it does not find something (~ fields are empty in the WOCR), it reads the work center determination table /SCWM/TPACKSTDT via FM /SCWM/TPACKSTDT_READ_SINGLE. Note that you can maintain records in this table via the easy access menu or directly call transaction /SCWM/PACKSTDT:
SAP EWM work center determination for packing_08
SAP EWM work center determination for packing_07
The FM first tries to read a record with the full key (route + activity area + consolidation group) before it applies the access sequence which you can define in customizing:
SAP EWM work center determination for packing_09
SAP EWM work center determination for packing_10

…and that’s it already. It is not foreseen to skip this step based on the rules-based flag. That means in case the rules-based flag is active and EWM neither finds a destination based on the 2 options described above (neither via the WOCR, nor in the work center determination table), you will receive an error message during warehouse task creation:

SAP EWM work center determination for packing_11
That also means that EWM will not consider the destination data from the process step in case the rules-based flag is active but the destination data is maintained (e.g. like in the screenshot below). Actually EWM will not even allow to save such a setup:
SAP EWM work center determination for packing_14
SAP EWM work center determination for packing_13

Sidenote – Consideration of the putaway strategy

Note that for any of the three options described here it is possible to provide only the destination storage type but leave the storage section and/or bin empty. In this case, EWM will determine the actual bin via FM /SCWM/PUT_BIN_DSTGRP. However, this will only return anything, in case you are using putaway rule ‘3’ (consolidation group) for your work center storage type:

SAP EWM work center determination for packing_12

Options for enhancements

As usual, I close my blog by giving you some ideas and options that you can use to implement a custom logic.
In case what I described above is not sufficient to cover your requirements, you can add your own packing station determination rule here via Badi /SCWM/EX_WRKC_PACKDET (Called at the end of FM /SCWM/DET_PACKING_STATION).
A second option is sitting at the end of the FM /SCWM/STORAGE_CONTROL_P_GET, where EWM calls Badi /SCWM/EX_CORE_PSC_PROCESS which can be used to implement your very own rules-based determination of the destination data for any of the given POSC steps.

Closure
As a resume I think we can agree that the work center or packing bin determination is very flexible but at the and not complex at all. I hope that I could explain and visualize everything in a way that it helps you within your current or any future projects!

I hope this blog post provides value to you and you could learn something. Please feel free to subscribe to my blog updates or my youtube channel in case you want to be notified about new posts!

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