SAP MM controls how materials move inside a company and how materials are bought from outside vendors. Every material request goes through system checks before SAP decides what action to take. The system does not rely on user choice. It relies on rules, settings, and master data. If these are not understood clearly, companies face issues like wrong purchasing, stock mismatch, or delays. Learning this logic is an important part of any SAP MM Course because this is where most real project problems come from.
How SAP Detects a Material Requirement?
A material requirement can come from many places in SAP. It may come from production planning, plant maintenance, quality checks, sales orders, or direct user input. SAP MM does not decide immediately whether the request is internal or external. First, it reads master data and plant-level settings.
SAP checks the following before doing anything else:
- Material type
- Procurement type
- MRP type
- Stock management indicator
- Valuation control
- Plant assignment
- Storage location relevance
In SAP, inventory checks occur for stock-managed materials, while non-stock items proceed directly to procurement. MRP-relevant materials are processed during planning runs, whereas non-MRP items are handled in real time.
SAP does not create documents randomly. It creates them only after these checks are complete. If the system logic is wrong, the document created will also be wrong.
Internal Material Requests and Stock Usage Logic
Internal material requests mean SAP believes the material can be supplied from existing stock. In this case, SAP does not create a purchase document. Instead, it creates a reservation or allows direct stock issues.
Key points about internal material requests:
- Stock must exist at plant level
- Material must be allowed for internal procurement
- Correct movement type must be used
- Account assignment must be valid
SAP uses reservations to block stock. This ensures that the same material is not used by multiple processes. Reservations are important for planning and availability checks.
Internal material requests still impact finance. When stock is issued:
- The system reduces the material value.
- The system debits the cost object.
- The system credits the inventory account.
Special stock types add more rules. SAP treats each stock type separately.
Common internal stock types include:
- Unrestricted stock
- Quality inspection stock
- Blocked stock
- Project stock
- Sales order stock
SAP will not use special stock unless it is allowed. For batch-managed materials, SAP also checks batch validity, expiry, and status.
Internal requests are common in manufacturing and maintenance processes. Many learners from SAP MM Course in Hyderabad face issues where stock exists but SAP does not allow consumption. This usually happens because of wrong stock type, batch status, or plant-level restrictions.
External Material Requests and Purchase Flow
External material requests happen when SAP decides that stock cannot be used. In this case, SAP creates a purchase requisition. This is not a user choice. It is a system result.
SAP creates a purchase requisition when:
- Stock is not available
- Material is marked as external procurement
- Material is non-stock
- Service is required
- MRP planning triggers procurement
A purchase requisition contains technical details that control the next steps.
Important fields in external requests:
- Account assignment category
- Item category
- Plant and storage location
- Material group
- Delivery date
- Quantity and unit
SAP also checks source determination. If vendor data exists, SAP can suggest or fix a vendor automatically.
Release strategy controls approvals. SAP blocks the requisition until approval is complete. This is rule-based, not manual.
Quota arrangement can split demand across vendors. SAP calculates quota automatically and assigns vendors based on percentage rules.
In large setups connected to SAP MM Course in Bangalore with Placement, external material requests are often fully automated. Purchase requisitions are created by MRP runs and sent for approval without manual creation. This makes correct configuration very important.
How SAP Decides Internal or External Request?
SAP does not follow one rule. It checks multiple factors at the same time.
Main decision factors include:
- Stock availability
- Procurement type in material master
- MRP settings
- Special stock indicators
- Account assignment
- Valuation type
SAP evaluates these together and then creates the right document.
Internal vs External Logic Table
| Check Area | Internal Request | External Request |
| Stock available | Yes | No |
| Document created | Reservation | Purchase requisition |
| Vendor involved | No | Yes |
| Accounting impact | Consumption posting | GR and invoice |
| Processing time | Immediate | Planned |
| Control method | Movement type | Release strategy |
Advanced systems may also use enhancements. User exits and BAdIs allow companies to change SAP’s default logic. This is common in large organizations with strict controls.
Common Technical Problems in Material Requests
Many SAP MM issues happen because users do not understand this logic.
Common problems include:
- SAP creating PRs even when stock exists
- Stock not getting consumed
- Wrong cost postings
- Approval delays
- Duplicate procurement
These problems usually come from:
- Wrong procurement type
- Incorrect MRP settings
- Missing account assignment
- Wrong stock type
- Ignored reservations
Sum up,
SAP MM handles material requests through system logic, not manual choice. Internal requests use existing stock and follow movement and valuation rules. External requests trigger purchasing and follow approval and vendor rules. Both affect finance, planning, and operations. Understanding this logic helps avoid errors, delays, and wrong procurement. It also helps SAP professionals troubleshoot faster and configure systems correctly. Strong knowledge of internal and external material request handling is essential for working on real SAP MM projects and managing business processes smoothly.
