As-Built BOM (aBOM)

As-Built BOM (aBOM) is the unit-specific record of exactly which parts, lots, serials, and revisions were installed on an individual product when it left the factory. Where the EBOM and MBOM are master representations, the aBOM is per-serial-number — the truth of this physical unit.

What it covers

• Serialized component instances with manufacturer, lot, and date-code for each line.
• Approved substitutions and deviations consumed during the actual build.
• Effectivity at unit/serial granularity — links to the work order, route step, and operator.
• Genealogy / pedigree for regulated products (FDA UDI, aerospace lifing).
• Foundation for as-maintained (aMBOM) and field-service service BOMs.

Relationships (see sidebar)

• Part of the broader MBOM/EBOM BOM family — derived at production time from the MBOM plus actuals.
• Supports Manufacturing Execution, Warranty and Field Feedback, and Service and Maintenance.
• Implemented by PLM platforms paired with MES, including Siemens Teamcenter and PTC Windchill.