BoMs

Bills of materials (BOMs) are structured lists that specify the components, subassemblies, materials, and instructions required to manufacture a product. A BOM acts as a recipe that connects design data to manufacturing and sourcing processes. It typically includes part numbers, quantities, units of measure, reference designators, and sometimes supplier information and cost.

Different kinds: An engineering BOM (EBOM) captures the product as designed; a manufacturing BOM (MBOM) translates the EBOM into the components needed to build a finished item in production; a sales or service BOM may show parts needed for service parts or configurations. BOMs can be single-level or multi-level, the latter expressing assemblies within assemblies. Phantom items, kits, and configurable BOMs may be used to model optional features or subassemblies that are not stocked.

BOMs are used in product data management and enterprise resource planning systems to drive material planning, procurement, inventory management, and cost calculation. BOM explosion expands the hierarchy to determine exact materials and quantities for a given production order. Accurate BOM data is essential for scheduling, budgeting, and traceability.

Managing BOMs involves version control, change management, and lifecycle status. Changes are typically released with a revision, affecting downstream processes such as procurement and manufacturing. Data quality, standardization of part numbers, and alignment with the item master are critical for effective BOM governance.

Industries such as electronics, automotive, and consumer products rely on BOMs to coordinate design and manufacturing. Standards and practices may vary across industries, but every BOM serves to define what is needed to produce and assemble a product.