Material Requirements Planning: Process Details

When material requirements planning (MRP) is performed, the system analyzes particular data based on MRP settings and existing open documents that may influence the planning. In this topic, you will find information about how MRP works in Acumatica ERP Manufacturing Edition.

Data Used in MRP

During MRP, the system analyzes supply and demand documents. Demand documents are documents that generate demand for items and cause items to be issued from one of the company's warehouses. The demand document may be a sales order, a forecast, or a production order for materials included in an item to be produced. Supply documents are documents that supply items required in production and cause receiving items in one of the company's warehouses. The supply document may be a purchase order or a production order for an item to be produced.

The system also considers the other data stored in the system that may affect item availability. The extended list of documents and data used in MRP is the following:

  • Forecasts
  • Sales orders that are not processed until completion, including open transfer orders and blanket sales orders
  • Shipments with not issued items
  • Inventory on hand
  • MPS orders
  • Production orders that are not processed till completion
  • Purchase orders that are not processed till completion

You manage the set of entities included in planing at the warehouse level. For details, see MRP Configuration: General Information.

Components Used for MRP

During material requirements planning, the system analyzes which components of items to be produced will be needed and suggests creating purchase orders if it discovers any shortage. The system determines the needed components as follows:

  • For production orders, the material details with a quantity remaining are always used.
  • For planned orders, the most recent active revision of the bill of material, whose identifier is specified in the Planning BOM ID box on the Manufacturing tab of the Stock Items (IN202500) is used. If this box is empty, the bill of material specified in the Default BOM ID box on the same tab is used.
  • For master production schedule (MPS) orders, the bill of material specified in the order is used.

Additionally, the system uses the effective start date and effective end date specified for each material line in the bill of material to determine if a component is effective at the time when planned orders are generated.

The system selects the active bill of material based on the effective dates of the BOM revision. For example, if a revision exists for a future start date, it will be used for planned orders with a start date on or after this date.

Order of Creating Planning Orders

During MRP, the system analyzes the hierarchy of items based on the bills of material assigned to items and starts creating planning orders from the top-level items. It generates low-level codes for each item and component. The top-level items, such as items to be produced, are assigned the zero code. Then the system analyzes the components of the top-level items and assigns them the 1 code. If any of the components is a subassembly, which also should be produced, the system then analyzes its components and assigns them the 2 code. This procedure is repeated until the lowest level of components is reached.

Dates on Supply and Demand Orders Used in MRP

The system uses the following dates specified in supply and demand documents during MRP:

  • Sales orders and transfer orders: The Ship On date in each document line on the Sales Orders (SO301000)
  • Purchase orders: The Promised date in each document line on the Purchase Orders (PO301000)
  • Production orders: The Start Date of each operation on the Production Order Details (AM209000) form
  • MPS orders: The Start Date of each operation on the MPS Listing (AM000004) form

Consolidation of Demand Documents

If the Use Days of Supply to Consolidate Orders check box is selected in the Consolidation section of the MRP Preferences (AM100000) form, the system consolidates items with the same ID from multiple demand documents into a single planned order during MRP. (For more information, see MRP Configuration: System Settings.) The system uses the earliest requested date from the demand documents of the group as the action date of the planned order.