1) Net Requirement Calculation
2) Lot-Size Procedures / Calculation
3) Procurement Types / Proposal
4) Scheduling
5) BOM Explosion
1) Net requirement calculation
- A comparison of firmed receipts & requirements takes
place along time axis.
- If a material shortage occurs then the system calculates
a net requirement.
- Available Qty is Stock-Safety Stock.
- Net requirement = Total requirement - Avail Qty.
- You can define the available part of the safety stock
in a MRP group.
- New order proposals are not created until stock levels
have fallen below the available portion of safety stock
2) Lot size Procedures
There are 3 Lot sizing procedures in SAP R/3 Static, Periodic & Optimum lot sizing.
a) Static lot sizing
–Lot-to-lot order quantity
–Fixed lot size
–Replenish up to maximum stock level
b) Periodic lot sizing
–Daily lot size
–Weekly / Monthly lot sizing
–Flexible periods according to planning calendar
c) Optimum lot sizing
–Part period procedure
–Least unit cost procedure
–Gross reorder procedure
–Dynamic lot size creation
-Net requirements are used in lot size calculations to
determine the quantities of the individual order proposals
-For period or optimum lot-sizing procedures, several
net requirements are clubbed together in one order proposal.
-Lot sizes can be restricted by using options
-–Define maximum or minimum lot size
-–Rounding value functions
3) Procurement types
- Procurement types define whether a material is produced
in-house or procured externally.
- If the procurement type is “E” then the system always
uses in-house production time.
- If the procurement type is “F” then the system always
uses Planned delivery time
- All other types of procurement like stock transfer,
sub-contracting, production in other plant are carried out using special
procurement key.
- Procurement key & special procurement key are available
in MRP-2 screen of material master.
4) Scheduling
Backward Scheduling
- The goods receipt processing time specifies the number
of workdays required by the stores person to check the material received
& to place it in stock.
- In-house production time is calculated by adding lead
time & the floats before & after production.
- The opening period represents the processing time required
by the MRP controller for converting the planned orders.
Forward Scheduling
- The system schedules forward starting from the basic
start date.
- "today" scheduling: The system carries out forward
scheduling using the current date as a basic start date.
5) BOM explosion
- In BOM explosion, the system calculates the components
or assemblies required for the appropriate BOM
- The key date for evaluation of the BOM (Explosion date)
is the order finish date of the planned order
- Using the lead time offset in the BOM you can displace
the dependent requirements date of a specific component.
