Bill of Materials (BOM)
A Bill of Materials (BOM) is the structured, multi-level list of every part, sub-assembly, raw material, and (increasingly) every piece of software and electronics that goes into a product, with quantities and relationships. PLM manages multiple views of the BOM: the engineering BOM (eBOM) reflects how the product is designed, the manufacturing BOM (mBOM) reflects how it is built, and the service BOM (sBOM) reflects how it is maintained. The BOM is the spine of PLM — every other capability hangs off it.
In context
In automotive, the eBOM from CATIA defines functional subassemblies — door panel, regulator, window glass — organized by design hierarchy; manufacturing then transforms this into the mBOM organized around assembly line stations, a transformation managed in Teamcenter or Windchill. An incorrect eBOM-to-mBOM transformation is one of the most common sources of production launch errors in new vehicle programs.
Why it matters
The BOM is the single artifact that has to be right for almost everything else to work — manufacturing instructions, costing, regulatory submissions, recalls, spares, sustainability reporting, AI-driven decision support. The eBOM/mBOM/sBOM split also explains a lot of cross-functional friction in manufacturing companies: each function thinks of 'the BOM' as theirs, and PLM exists largely to keep those views reconciled. In the real world, much of the eBOM-to-mBOM conversion still happens in Excel — the most common point where the digital thread fractures.
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External References
This term appears in
- The New Generation: 30+ Startups Proving PLM Disruption Is Real
- PLM History 101: PDM (Part 6) - Toward PLM and the Digital Thread
- eBOM to mBOM: Why the Translation Gap Persists and How to Fix It
- PLM vs PDM: What's the Difference, and Which One Do You Actually Need?
- PLM for Small and Midsize Manufacturers: A Practical Adoption Guide
- Discrete Manufacturing PLM vs Process Manufacturing PLM: What's Different and Why It Matters
- What Is BOM Management? The Core of Product Data in PLM
- What is PLM? A Plain-English Definition for 2026
Cite this definition
Finocchiaro, Michael. “Bill of Materials (BOM).” DemystifyingPLM PLM Glossary, 2026, https://www.demystifyingplm.com/glossary/bill-of-materials