What Is a Bill of Materials?

Bill of Materials (BOM) is a technical document describing the composition of an enterprise's products. In the processing capital industry, it indicates the structural relationship between the product's final assembly, sub-assembly, assembly, component, part, up to the raw material, and the required quantity.

All child assemblies, middleware, parts, and raw materials that make up the parent assembly

The BOM (Bill of Materials) in the narrow sense is usually called "bill of materials", which is the product structure. It only expresses the simple decomposition of the physical structure of the material according to certain division rules, and describes the physical composition of the material. It is generally divided and described in terms of functions.

In a broad sense, BOM is a combination of product structure and process flow, and the two are inseparable. It is not practical to talk about product structure without the process flow. To objectively and scientifically describe a manufacturing product through BOM, we must start with the manufacturing process to accurately describe and reflect the structure of the product.

BOM (Bill of Manufacturing) =

Bill of materials (BOM) is a description of a final product

BOM type (standard, model, plan, option class)

1. Standard BOM: The BOM of standard materials. Standard materials refer to materials other than planned materials, option classes, or models included on the bill of materials, such as purchased parts, self-made parts, and outsourced parts. The standard bill of materials is the most commonly used type of list, which lists statutory components, the required quantity of each component,

The BOM is a technical description file of the product structure. It not only lists all the constituent items of the final product, but also indicates the structural relationship between these items, that is, the hierarchical membership relationship from raw materials to parts and components to the final product, and their The quantitative relationship between. The BOM is the core file of a manufacturing enterprise. The BOM is used by various departments and systems to obtain specific data from the BOM.

The design department is the designer of the BOM and the user of the BOM. It needs to obtain information about all parts and mutual structural information from the BOM.

The technology department establishes the manufacturing process and assembly process of each part according to the BOM, as well as the tooling, molds, etc. that should be used in the manufacturing process;

When using computer-aided production management, the computer must first be able to read out the composition of the products manufactured by the enterprise and all the involved products.

The bill of materials is the core document of a manufacturing company. Bills of materials are used in the activities of various departments, and production departments produce products based on bills of materials.

For the ERP system to function properly, the bill of materials must be complete and accurate. Otherwise, it is impossible to produce or purchase the right materials at the right time and in the right quantity. This has a number of serious consequences:

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(1) Site inspection: Have the product engineer go to the assembly site and compare the actual assembly situation with the bill of materials. These engineers work closely with the foreman and assembler to find errors and correct them immediately.

(2) Office review: form a team of engineers, foremen, material planners, and costing staff to review the bill of materials. Find errors and correct them immediately.

(3) Product dismantling: Dismantle a final product, compare the parts and their number with those listed in the bill of materials, and correct the errors found. This may be a good approach. However, if the product is too large and complex, such as a jet aircraft, this method may not be applicable. Another disadvantage is the difficulty in identifying subassemblies.

(4) Unplanned in and out: When the production personnel return to the warehouse to collect more parts, it may be because they have some scrap products, or it may be because they have not received enough at the beginning. In the latter case, the bill of materials may be wrong, causing the picking list to be wrong. If some parts are returned to the warehouse after the assembly of a product, it is likely that they should not be taken away from the beginning. Also, the picking list is wrong due to a mistake in the bill of materials. In both cases, once errors are found, they must be corrected immediately. This method is also a good method for continued maintenance of material accuracy.