A difficult MRP topic appears in many manufacturing industries: the same raw material can have several qualified suppliers, but a specific finished product may only allow one supplier, or a limited set of suppliers.
This is not a rare edge case. It can come from customer certification, regulation, process validation, or strategic supplier agreements. The difficulty becomes greater when multi-level BOMs are involved.
Why common solutions are not enough
Manual control is common in reality, but it relies on planners, buyers, and warehouse teams remembering the constraint every day. Splitting material numbers by supplier keeps the rule visible, but quickly makes BOMs, substitutes, and master data difficult to maintain.
Batch attributes can help execution: receiving records supplier information and goods issue checks the allowed batch. But standard net-requirement calculation may still see only total stock and miss the supplier dimension. A self-developed simplified MRP can also fail if it cannot handle time-phased availability and purchase requisition generation.
What the planning result should carry
- The material number should usually remain unified instead of being split only for supplier control.
- Supplier constraints should come from BOM, routing, customer, product, or another clear rule source.
- MRP should distinguish total stock from supplier-qualified available stock.
- Purchase requisitions should carry the supplier constraint so purchasing and execution inherit the rule.
- Goods issue should still validate batch or supplier compliance at execution time.