Phantom Assembly in SAP PP: Setup, Example and MRP Behaviour
phantom assembly in sap pp example
Also searched as
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- phantom BOM SAP MRP behaviour
- how to configure phantom assembly in SAP
- phantom item vs phantom assembly SAP
Short answer
A phantom assembly is a sub-assembly that exists in the BOM but is never stocked or produced as its own order. In SAP set special procurement key 50 on the phantom's MRP 2 tab and give it a BOM. MRP passes the requirement straight through to the phantom's components and the parent production order picks up those components directly.
Applies to: SAP ECC 6.0 and S/4HANA on-premise, discrete and repetitive manufacturing. Applies to MRP via MD01 / MD01N.
How to configure a phantom assembly
- 1Create the phantom material (MM01) with its own plant data. Use a normal material type such as HALB for semi-finished.
- 2On the MRP 2 tab, enter special procurement key 50 (phantom assembly) in the Special procurement field. Key 50 is delivered in table T460A.
- 3Create the phantom's BOM in CS01 with its components. No routing is needed for the phantom itself.
- 4In the finished good's BOM (CS01 or CS02), add the phantom as a component with the quantity needed per parent.
- 5Run MRP (MD01N). Open MD04 for the finished good and for a component, and confirm the phantom itself has no planned order.
- 6Create a production order for the finished good (CO01). In the component list the phantom is exploded and its components appear on the parent order directly.
- 7Cost the finished good (CK11N) and verify the phantom's component cost rolls into the parent.
Example
A bike is made of a frame, a wheel set and a brake kit. The brake kit is bought as loose parts and is always fitted at the same moment as the wheels, never stocked. Model it as a phantom: bike BOM contains the frame, wheel set and brake kit (phantom). The brake kit BOM lists the lever, cable and pads.
When you plan 100 bikes, MRP does not create a planned order for 100 brake kits. It carries the demand through to the lever, cable and pads. The bike's production order lists lever, cable and pads as components, not the brake kit.
Bike (FERT) BOM: Frame x1, WheelSet x1, BrakeKit x1 (phantom) BrakeKit (HALB) MRP2 Special procurement = 50 BrakeKit BOM: Lever x2, Cable x2, Pad x4 Plan 100 Bike -> demand 200 Lever, 200 Cable, 400 Pad No planned order for BrakeKit
MRP and BOM explosion behaviour
The phantom is skipped as a planning level. MRP reads the phantom's BOM and moves the requirement to the next level, so its components use the low-level code the phantom would have had. If the phantom is also bought or used as a spare part, it can still carry a stock and be planned when needed because key 50 can be overridden in a different plant.
A phantom can be nested: a phantom inside a phantom explodes through both levels. Keep nesting shallow, because it makes the production order component list harder to read.
Special procurement versus the BOM item setting
Special procurement key 50 is set on the material in the plant, so it applies to every BOM that uses the material. A BOM item can also carry a phantom setting, which applies to that one use only. Use the material setting when the assembly is always phantom, and the item setting when the same material is sometimes a real stocked part.
Costing and reporting impact
Because the phantom has no order, its cost does not appear on its own. Product costing (CK11N) rolls its components up into the parent. Inventory reports will not show phantom stock, and the work in process of the phantom is not tracked separately, which is the point and also the limitation.
Try it here, free
SAP Procurement Type and Special Procurement Key Reference
Quick reference for procurement type E/F/X, standard special procurement keys and BOM item categories and what MRP does for each.
Common pitfalls
- !Giving the phantom a routing and expecting operations to appear.
- !Setting key 50 in only one plant while another plant plans the phantom.
- !Using a phantom for something that is really stocked, hiding its inventory.
- !Deep phantom nesting that makes production order component lists long and hard to read.
- !Forgetting to re-run MRP after changing the special procurement key.
How an ERP-grounded AI assistant handles this
An assistant grounded in SAP can explode a BOM, flag components that are phantoms and show why a planned order was not created for a sub-assembly, using the same BOM tables (STKO, STPO) and MARC fields. On-prem, Netray keeps that read-only and local, which matters for aerospace and defense BOMs that cannot go to a public model.
Frequently asked questions
What is a phantom assembly in SAP?
It is a sub-assembly that appears in the BOM for structure but is not stocked or made as its own order. MRP and the production order pass through to its components, so the parent order shows those components directly.
What special procurement key is used for a phantom?
Key 50, Phantom assembly, entered on the MRP 2 tab of the material in the plant. It is delivered in table T460A. A phantom can also be flagged at BOM item level for a single use.
Does MRP create planned orders for a phantom?
No. The phantom is exploded and its requirements move to its components, so there is no planned order, procurement proposal or stock for the phantom itself.
Can a phantom assembly have a routing?
It does not need one, because it is never produced as its own order. Operations belong to the parent's routing, which is where the labour for fitting the phantom's parts should be recorded.
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