In more than twenty years of project work, we have met many complex manufacturers that said the same thing: MRP is hard to run. Orders change, data is imperfect, capacity is unstable, BOMs are complex, and special scenarios appear everywhere.
These are real difficulties, but they do not prove that MRP is obsolete. More often, the project starts from the wrong understanding. MRP is not a fashionable planning slogan. It is the basic discipline of supply and demand: what is needed, when it is needed, what can be consumed, and what should be created.
If a company has orders but still lacks materials, and also has plenty of stock that cannot be used, the problem is usually not capacity. It is supply-demand matching.
Misunderstandings we see often
- Surplus capacity is mistaken for a reason to ignore MRP.
- People assume real-time MES data is required before any MRP work can start.
- Business changes are treated as an obstacle, although MRP is built to recalculate after change.
- Complex BOMs, configurable products, substitutes, specified suppliers, and centralized purchasing are treated as reasons to give up, instead of scenarios that must be designed.
- Teams spend all their energy cleaning data, but do not spend enough time on the calculation scheme itself.
The harder part
MRP does not require perfect execution. It helps manage imperfect execution by comparing plan and reality, exposing deviations, and recalculating the next plan. It also does not require absolutely perfect data. It requires usable data and a mechanism that keeps improving data through daily use.
The scarce capability is not only system operation. It is the ability to design a workable MRP scheme for a real manufacturing business, including finance-related topics such as intercompany flow, centralized purchasing, and cost impact.