P2M 202 · STRUCTURE
What is a bill of materials—and when should an assembly be phantom?
A BOM defines the components and quantities needed to make a material. Phantom assemblies preserve a logical grouping but are exploded into their components rather than planned or produced as separate stock.
HOW IT WORKS
Finished-product demand becomes component demand
Demand for a finished product must eventually become demand for the materials needed to make it. The Bill of Materials provides this product structure, so one requirement for a finished material can create requirements for assemblies, components, and raw materials further down the product structure.
Concept flow: Finished-product demand → BOM explosion → component demand. Phantom assemblies can organize the structure while their components flow directly into higher-level planning.
CAPABILITY MODEL
Understand the input, decision, and result
Read the capability as a connected planning decision before moving into detailed SAP controls.
Finished-product requirement
A requirement for the finished material establishes what the business wants to make.
BOM relationship
The valid BOM expresses which assemblies and components, in what quantities, support that material.
Dependent demand
Planning can explode the structure into lower-level material requirements.
OPERATIONAL FLOW
How the capability performs
The sequence connects business need to a planning or execution result.
Choose the valid structure
Material, plant, usage, alternative, validity, and change context identify the BOM that applies.
Translate the requirement
The finished-product quantity is multiplied through the component relationships to create lower-level demand.
Read the assembly intent
A stocked or produced assembly remains a planning object; a phantom grouping organizes structure without creating separate stock.
Feed planning and execution
The resulting component requirements support MRP and later production-order construction.
DESIGN & CONTROL
What shapes the result
These controls work together; a locally correct setting can still produce the wrong planning outcome.
Structure validity
Usage, alternative BOM, validity dates, change numbers, and plant determine which structure applies.
Component meaning
Item category, quantity, scrap, and unit relationships determine how demand is translated.
Assembly policy
Make, buy, stock, or phantom treatment determines whether an assembly receives its own supply response.
DIAGNOSTIC EVIDENCE
What proves the result?
Use the business input, system objects, and resulting state together.
Material, plant, BOM header, components, quantities, units, and validity.
Finished-product requirement, dependent requirements, and the selected structure reference.
Production order components and the BOM or production-version selection used for the run.
PLANNING MOMENT
A pump requires a seal kit, but the kit is never stocked or produced separately.
The BOM keeps the seal kit as a logical grouping while the valid phantom setting lets planning and the production order see the individual seals directly.
- Structure is valid for the plant
- Quantities explode correctly
- Phantom intent is deliberate
- Order components match planning
IN SAP
Simple representation
These are the main planning objects to recognize before moving into detailed controls.
Material · BOM header · BOM components · Quantity relationships
How SAP controls it
BOM usage, alternative BOMs, item categories, validity dates, change numbers, component quantities, and phantom-item settings determine which components planning and production use.
A finished pump uses a phantom seal kit: MRP and the production order see its seals directly, without creating stock or a separate order for the kit.
Connect this capability to the complete execution and integration story.