Bill of materials

Bill of materials

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Bill of materials

Bill of materials (BOM) is the term used to describe the raw materials, parts, sub-components, and components needed to manufacture a finished product. It may be used for communication between manufacturing partners,^[1] or confined to a single manufacturing plant.

BOMs are hierarchical in nature with the top level representing the finished product which may be a sub-assembly or a completed item.

The first hierarchical databases were developed for automating bills of materials for manufacturing organizations in the early 1960s.^[2]

BOMs that describe the sub-assemblies are referred to as modular BOMs. An example of this is the NAAMS BOM that is used in the automative industry to list all the components in an assembly line. The structure of the NAAMS BOM is System, Line, Tool, Unit and Detail.

A bill of materials "implosion" links component pieces to a major assembly, while a bill of materials "explosion" breaks apart each assembly or subassembly into its component parts.

A BOM can define products as they are designed (engineering BOM), as they are ordered (sales BOM), as they are built (manufacturing BOM), or as they are maintained (service BOM).

The different types of BOMs depend on the business need and use for which they are intended.

A BOM can be displayed in the following formats:

single-level BOM
indented BOM
modular (planning) BOM

In process industries, the BOM is also known as the formula, recipe, or ingredients list

In electronics, the BOM represents the list of components used on the printed wiring board or printed circuit board. Once the design of the circuit is completed, the BOM list is passed on to the PCB layout engineer as well as Component Engineer who will procure the components required for the design.