Bill of materials (BOM)

The Bill of Materials or product tree as it is sometimes called, is a document or files which list the components or materials needed to manufacture a component or product. The Bill of materials should also contain the order in which the parts or sub-components are assembled as well as information relating to each part such as the material it is made out of, number of parts required, and whether it's a purchased or manufactured part. In some cases the bill of materials for a product or component will be accompanied by an assembly drawing showing how the sub-components or parts fit together.

An example of a simple Bill of materials:

Product Y

   Part B (2)
     Part B1 (1)
     Part B2 (1)
   Part C (3)
   Part D(1)

This would be interpreted as Product Y is built with 2 parts of Part B, 3 of Part C, and one of Part D. Part B is built with one unit of sub component B1 & B2.

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