We come across specific business requirements where in a vendor delivers the component concerned only on specific day/s and it makes sense to plan the component accordingly based on the delivery pattern. Time-Phased Planning (TPP henceforth) steps in here to accomplish this.
Contrasted with MRP, TPP will not consider the entire horizon during which the dependent requirement exist for the component and thus differs from conventional MRP which plans for entire horizon. Needless to say the Netchange indicators are relevant only for MRP and not TPP. In technical parlance, Time-Phased planning delays release of procurement proposals for components until they are actually needed and offsets the requirements by the lead time concerned.
Where does TPP fit in the planning procedure scheme of things?
Core ERP/ECC supports 3 types of planning procedures:
1. Master Production Scheduling (MPS)
2. Materials Requirement Planning (MRP)
3. Consumption Based Planning (CBP)
CBP is again divided into:
1. Reorder Point Planning (ROP)
2. Forecast-based planning (FBP) and
3. Time phased planning (TPP)
Even though TPP is ‘functionally’ placed under CBP by design/default we can utilise it with the MRP planning procedure after making changes relevant to the MRP type we use. Meaning to make use of TPP with MRP we would definitely need a customised MRP type.
In SAP standard,
MPS items have a MRP type beginning with M* (M0/M1/M2/M3/M4)
MRP items have a MRP type beginning with P* (PD/P1/P2/P3/P4)
ROP and FBP items have MRP type beginning with V* (VM/V2/VB/V1/VV)
TPP items have MRP type starting with R* (R1/R2/VS)
All remaining types are for Retail-relevant functionalities (RE/RF/FP/RR/RS/VI).
Other two MRP types are X0 and ND making the total MRP types in standard as 26.
And obviously the disadvantage of TPP is you will not find it attractive if you have dual sourcing in place for the same component. Delivery from two vendors supplying the same component may vary and can be on different work days of the week. In such a case in the core ECC version we do not have the option to enter specific delivery pattern as we can enter only one delivery option/calendar at the material/plant level. This issue of vendor specific calendars per material is taken care of in the retail system which has specific MRP types to meet the requirement.
Even though the MPS/MRP and even ROP functionalities are available in massively enhanced forms in advanced planning systems like APO, we however do not have an alternative to TPP elsewhere for that matter, making TPP as ECC-specific.
For this discussion, we will see a basic scenario of TPP with MRP. For this purpose we have created a customised MRP type Z9.(Details as below).
FERT11 is the Assembly and ROH11 is the BOM component/dependent requirement associated.
ROH11 is assigned to MRP type Z9 that supports TPP and makes it mandatory to use a Planning cycle (CL1 in our case). Also we can use a delivery cycle (CL2 in our discussion) created as per our requirement, in MRP2 view. Note that Planning cycle is mandatory in TPP, where as it is optional to use Delivery cycle depending on our business requirement.
Even though the name appears as Planning calendar in MRP2 view it actually refers to the delivery period as below.
Customized MRP type Z9 has been created to ensure that it works in conjunction with MRP.
(The indicator Time-phased with Reqs ensures that the MRP type works with MRP procedure else if unchecked it can work only with CBP procedure with the appropriate settings).
CL1 Planning calendar details:
Planning for the material will happen only on Mondays and Wednesdays of every week.
CL2 Delivery calendar details:
Delivery for the material will happen only on Tuesdays and Thursdays of the week only.
We will load some planned independent requirement for FERT11 and run MRP.
When we run Single item multi-level MRP by default it plans for all levels below.
We have loaded a demand of 50 numbers split across 4 days.
MD02: Single-Item Multi-level planning
We have set the parameters to display the results of planning run before they are saved.
In the subsequent run we see the results for FERT11.
After saving the data the planning run gets completed with out planning for ROH11.
(The planning run today as per the demo is Monday the 14th Nov’11 again).
This is expected as the TPP items are not planned against the higher assembly but independently. It should be noted that the dep reqmts are already inherited by the TPP items after a planning run for higher level assemblies.
In a typical business scenario we actually would be running Total planning/MD01/MDBT for the plant and this material will be automatically planned on a Monday or a Wednesday as the case is.
When TPP is used (as per the MRP type) the system writes down the ‘Planning date’ for the material concerned in what we call as the Planning File entry (PFE) as in MD21 txn.
For MRP type PD materials this field is not populated and remains blank and this field is specific for TPP only.
Note: The planning date is proposed based on the planning cycle CL1 in the material master. This can be changed as per the requirement and planning executed on Non-planning dates also using MD20 again.
Now execute Single-item single-level planning for ROH11 using MD03 txn.
Planning results are as follows:
After the planning run is completed the next planning date is reset to the ensuing planning date which is the Thursday (16th Nov’11 in our case) as per CL1 calendar.
Explanation of results for ROH11:
Planned delivery time is 18 days as in material master.
[Also the MRP4 view Ind/Collective requirements is set as 2 (Collective reqmts only). So system will club all related requirements/demand while creating a procurement proposal. Here the system has clubbed the first 3 requirements and created a PReq for 37 numbers.]
What system does during TPP?
It creates a planning time/horizon which is equal to
Planning date + Purchasing Processing time + Planned Delivery time + GR Processing time to identify the demand it has to satisfy.
In our case, Purchasing Processing time and GR Processing time are zero and so from today the system calculates 18 calendar days which is 2nd Dec’11 and tries to satisfy the demand with in the horizon. Outside of it the demand for 12th Dec’11, we see that it is not considered.
Because delivery can happen only on a Tuesday or Thursday the system has created the Pur Req for 6th Dec’11 (Tuesday) which is the next possible delivery date.(and not on 2nd Dec’11).
Let us now change the Planned Delivery Time as 23 days now and check the results.
Initially the planning date was 14th Nov’11 and had later moved to 16th Nov’11.
We will run MRP again with Planning date as 16th Nov’11 now.
So calculation will be based on Planning date as 16th Nov’11 running through 23 days which is 9th Dec’11 which is a Friday and hence it will consider a delivery for Dec13th, 2011 and also include the last dep reqmnt for FERT11 also and create a PurReq for 50 numbers instead of the existing 37 numbers.
Execute MD03 –Single-Item Single-level:
Results are as expected: