what is a bill of materials

A bill of materials (BOM) is a comprehensive list of parts, items, assemblies, subassemblies, intermediate assemblies, documents, drawings, and other materials required to manufacture, construct, or repair a product or service. It includes the raw materials, sub-assemblies, intermediate assemblies, sub-components, parts, and the quantities of each needed to manufacture an end product. A BOM may be used for communication between manufacturing partners or confined to a single manufacturing plant. The BOM is often shown in a hierarchical way, with the finished product at the top, followed by individual components and materials. It can be presented as an explosion display or an implosion display. Most BOMs include the following elements: BOM level, the part number, name, description, and quantity, cost, and the unit of measure. A BOM is an important part of the engineering and manufacturing process, as it is a comprehensive list of all parts and materials required to build a product, and an accurate BOM is vital to reducing waste, streamlining production, and ensuring the availability of necessary parts. The advantages of using a BOM include estimating the cost of materials, planning purchases, ensuring availability of parts, and avoiding delays in production.