Article 49: How does MRP integration create Purchase Requisitions automatically?
How does MRP create Purchase Requisitions?
Material Requirements Planning (MRP) is the most common source of automatic Purchase Requisition creation. When MRP detects a material shortage for externally procured items, it generates a PR as a procurement proposal.
When does MRP generate PRs?
Shortage Detection
MRP identifies shortages when:
- Current stock + scheduled receipts < total requirements
- Safety stock levels fall below minimum
- Reorder point is reached for reorder point materials
- Planned consumption exceeds available inventory
Material Requirements Analysis:
- Sales orders creating demand
- Production orders needing components
- Planned independent requirements (forecasts)
- Reservation requirements for projects
Procurement Type Determination
For PR generation, material must have:
- Procurement Type "F" (External procurement)
- MRP Type that allows planning (e.g., PD, ND)
- Valid vendor or source list
- Active planning parameters
What information does MRP include in PRs?
Automatic Data:
- Material number and description
- Required quantity to cover shortage
- Delivery date based on requirement timing
- Plant and storage location
- MRP controller as default requisitioner
Calculated Fields:
- Order quantity based on lot sizing rules
- Delivery date considering procurement lead time
- Source of supply if source list exists
- Account assignment from material master
How does lot sizing affect PR quantities?
Lot Sizing Rules
Lot-for-Lot (EX):
- Orders exact shortage quantity
- Minimizes inventory carrying costs
- Multiple small PRs possible
Fixed Lot Size (FX):
- Orders predetermined quantity
- May exceed immediate requirement
- Reduces ordering frequency
Replenish to Maximum (HB):
- Orders up to maximum stock level
- Considers current stock and outstanding orders
- Balances inventory and ordering costs
Example of MRP PR Creation:
Scenario:
- Material ABC123 has 100 units in stock
- Sales order requires 500 units next Friday
- Purchase lead time is 10 days
- Lot size rule is Fixed Lot Size of 1,000 units
MRP Logic:
- Shortage = 500 - 100 = 400 units
- Lot sizing = 1,000 units (minimum order)
- PR created for 1,000 units
- Delivery date = Friday - 10 days = Monday
How to process MRP-generated PRs?
Review and Release
Transaction ME57 (Convert PR to PO):
- Mass conversion of multiple PRs
- Source determination automatic
- Vendor selection based on conditions
- PO creation in batch mode
Individual Review (ME53N):
- Display PR details
- Verify requirements and timing
- Check source suggestions
- Manual conversion if needed
Modification Options
Before conversion, planners can:
- Change quantities if requirements updated
- Adjust delivery dates based on capacity
- Select different vendors if preferred
- Add special instructions or terms
What integration exists with other processes?
Source Determination:
- Automatic vendor selection from source lists
- Contract references for blanket agreements
- Quota arrangements for multi-sourcing
- Info record pricing and terms
Account Assignment:
- Cost center from material master
- Consumption accounts for direct materials
- Project assignment for project materials
- Order assignment for production consumption
Quality Management:
- Inspection requirements trigger quality PRs
- Vendor qualification status checking
- Certificate requirements specification
- Sampling procedures integration
How to optimize MRP PR creation?
Best Practices:
- Maintain accurate material master data
- Review and update lead times regularly
- Optimize lot sizing rules for cost efficiency
- Clean up obsolete or inactive materials
- Monitor PR conversion rates and timing
Performance Monitoring:
- PR creation volume and trends
- Conversion rates to POs
- Lead time accuracy vs. actual delivery
- Cost impact of lot sizing decisions