An effective BOM includes the following 11 core components:
- Levels. A bill of materials often contains several levels. The BOM level number explains where the part fits into the BOM hierarchy.
- Part name. A record of a part name helps manufacturers identify parts and provides information about them.
- Part number. Part numbers are used as shorthand to refer to and identify parts. An intelligent or significant part number denotes some information about the part. An insignificant or nonintelligent part number is an arbitrary number assigned to a part. For example, a screw might have an intelligent part number of HSC0424OP. The H means hardware, the S stands for machine screw, the C0424 refers to the length of the screw, and OP refers to the screw’s head style. The same screw in an arbitrary numbering system may use the serial number 000383487349, which has no additional meaning beyond identifying the screw.
- Manufacturer name. Listing the manufacturer’s name helps identify a part.
- Part phase. This indicates where each part is in the product lifecycle. For example, a new part would be in the unreleased or in-design phase. A revision level is sometimes included in the part phase to indicate the version or revision of the part.
- Alternate parts. This tells the reader whether a part can be swapped for another one if the original part is unavailable.
- Priority analysis. This defines which parts are critical and helps users prioritize purchasing. For example, components with higher monetary values and longer lead times might get priority.
- Description. This provides details of each part and helps the reader distinguish among similar parts by color and dimensions.
- Quantity. This indicates the number of components needed. A unit of measurement should be defined for each part type.
- Procurement specification. The procurement specification describes how parts are purchased and made. The designations P, M and C are often used — they stand for purchased, modified and custom.
- Comments and notes. This is a place to document unexpected changes and take notes as the project takes shape. Notes may include images and diagrams of a part or assembly.