Short-Term and Long-Term Lot Size 

Use

If you define a short-term and a long-term lot size for a material, you can split up the time axis for the material requirements planning into a short-term and a long-term area and thus carry out the procurement quantity calculation using two different lot-sizing procedures.

You can therefore, for example, group together requirements over a larger period in the long-term area to produce a rough picture of the future master plan and select a more precise lot size to suit your requirements in the short-term area.

Prerequisites

You have defined the settings for the short-term and long-term lot size in the IMG activity Check lot-sizing procedure in Customizing for MRP.

Features

During the planning run the system calculates the time axis for the validity of both lot-sizing procedures. The procurement quantities in the first, short-term area are calculated using the short-term lot size. From the valid from date of the long-term lot size the system switches to the long-term lot size.

If no long-term lot size has been specified for a lot-sizing procedure, the system plans the complete planning period using the short-term lot size.

Calculating the Long-Term Lot Size

The start of the effectivity period of the long-term lot size is determined using the number of periods specified in Customizing. The system always rounds up to the end of a period that has already started and then sets the valid from date to the beginning of the next complete period. The system normally offers period lot sizes for the long-term lot size. This ensures, that the period requirements grouping is always traceable within the defined period length of the period lot size.

The calculation of the date from which the long-term lot size is valid is 15 March. Four months have been entered for the periods for this calculation. The system calculates four months into the future (15 July) and then rounds up to the beginning of the next complete period. The long-term lot size is thus valid from 1 August.

You can also define a period for lot-for-lot order quantity in Customizing, which is set for the short-term and the long-term period. The system then always plans using lot-for-lot order quantity in this period, even if other lot-sizing procedures have been defined in the short-term and long-term period.