During my time working with Maximo I have found that the Item Assembly Structure feature in Maximo is rarely used or understood by Customers. I have written this blog with the aim to help users in the field to get the most out of this great feature.
IAS Feature definition
An item assembly structure is a list of spare parts and subassemblies required to build an Asset or to define the requirements of a location.
An Item Assembly structure is an Asset Template which list all its components and hierarchy. It is designed against the Item Master application in Maximo.
The parent Item number is used to identify the IAS which can be applied against the Asset or the Location. The parent Item must be flagged as Rotating to be able to be set against the Item field of the Asset / Location.
Example:
A Wind Turbine and its constituent parts are used in 10 rotating assets subassembly structures in a Wind Farm.
Each Wind Turbine is composed of 4 main sub Assets which will require planned Maintenance:
- A Rotor
- A Generator
- A Gearbox
- A Steel Tower
Rather than specifying the component parts and sub assemblies on all 10 asset records, the Wind Turbine Item Assembly Structure can be copied and applied to the 10 assets.
In our example, 5 rotating Item are created (Wind Turbine, Rotor, Generator, Gearbox and Tower) and the IAS is defined against the parent Item which is the Wind Turbine.
Creating the IAS
Once the top-level rotating Item (WF1001) has been created, children can be added to design the IAS.
- If the child is a rotating Item, then it will become a child Asset once the IAS is applied.
- If the child is a non-rotating Item, it will become a spare part once the IAS is applied.
See below our Wind Turbine IAS with 4 rotating Items and 3 spare parts:

– Figure 1: Item Assembly Structure in Maximo –
Applying the IAS
The IAS can be applied from the Asset application or from the Receiving application if a PO has been created to purchase the Assets.
Asset Application
- From the Asset Application, user creates a new Asset and populates the Top-level Item of the IAS in the Rotating Item Field.
– Figure 2: Add an Asset in Maximo –
- Apply the Item Assembly Structure.
– Figure 3: Apply the IAS in Maximo –
- By clicking on the Auto-number All button, system auto populates all the child Assets and the IAS is copied across the Wind Turbine Asset.
– Figure 4: Asset Subassemblies in Maximo –
- The Asset hierarchy is now designed in the system.

– Figure 5: Asset hierarchy in Maximo –
Receiving Application
In order to serialize multiple Rotating Assets, the Receiving application can be used assuming a PO has been created for the purchase of the Assets.
- From the receiving application, click on the Receive Rotating Item action. The below dialog appears with the 10 Wind Turbines ordered.
– Figure 6:Receive Rotating Items in Maximo –
Preview (opens in a new window) - Click on the Autonumber Button and the system auto populates the Asset Number.
- Select the first Asset. Click on the corresponding Apply IAS icon.
- The Apply IAS dialog gets displayed. Click on the Autonumber All button to populate the child Assets. Click OK and the IAS has been applied against the Asset selected.
– Apply Item Assembly Structure in Maximo –
- Repeat steps 3-4 for each rotating item received and to which you want to apply the IAS.
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