Time-Phased Planning Procedure (SAP Library - Material Requirements Planning (PP-MRP))

Time-Phased Planning Procedure

Prerequisites

In the material master:

You have entered an MRP type for time-phased planning and the planning cycle in the form of a planning calendar (MRP 1 view).
You have defined a planned delivery time (MRP 2 view).
You have entered lot-for-lot order quantity as the MRP lot size (MRP 1 view).

You can also use the optimum lot-sizing procedures for time-phased planning. They are used here in the same way as in reorder point planning.

You define MRP types in Customizing for MRP in the IMG activity Check MRP types.

Process Flow

When you start the planning run, the system uses the MRP date recorded in the planning file to check which materials are actually to be planned. The planning date is calculated using the planning cycle.

The system calculates requirements. It also then determines a time interval. This time interval must take into account that the material has to cover all requirements up to the next MRP date including the delivery time.

The requirements are calculated according to the following formula:

Forecast requirements - or other requirements in the interval (interval = planning cycle + purchasing processing time + planned delivery time + goods receipt processing time) + safety stock

The requirements of the periods that completely lie within the interval in question are taken into account when calculating the requirements. If a requirement does not completely lie within the interval, the system only takes part of it into account.

The planned delivery time is calculated according to calendar days and the purchasing processing time and the goods receipt processing time are calculated in workdays.

In the net requirements calculation, the system reduces the requirements calculated in the interval by stock and firmed receipts. The remaining quantity is equal to the shortage quantity.

If you use the lot-for-lot, the system creates a procurement proposal for the amount of the shortage quantity. If you have selected another lot-sizing procedure, the quantity in the order proposal depends on the lot-sizing procedure.

During the calculation, the system takes for granted that the firmed receipts lie in the interval in question. It does not matter whether the firmed receipts are available at the beginning or not until the end of the interval. This means that a temporary shortage may exist, however, this is accepted.