Bill of Materials (BOM) is an important source of information for manufacturing concerns. It is also known in different names such as assembly component list, production recipe or product structure. This article deep dives into the meaning and contents of the bill of materials and how to create one.
The Bill of Materials (BOM) refers to a comprehensive list of items, parts, assemblies and materials used or consumed to produce or manufacture a particular finished product. A BOM mentions the name, description, cost, and quantity of each material required. It also provides the instructions to use the specific parts and materials and the instructions for the procurement of these materials. Therefore, in short, it is referred to as a recipe to manufacture a particular product.
It also includes documents, drawings, subassemblies and intermediate assemblies. It is usually presented in a hierarchical format. The highest level represents the finished product, and the bottom shows all individual parts and materials.
The display can be either implosion or explosion kinds, depending on the manufacturer’s requirement. The explosion view of BOM displays the highest level of the product, such as the finished product itself and then breaks it into parts and components. Whereas the implosion view displays the inverse of an explosion view. It begins with the individual parts and connects to the final product or assembly.
A BOM is relevant at the beginning stage of product manufacturing to ensure the efficiency of the production process. It gives an idea about the availability of raw materials and assemblies to finish a product.
All manufacturers producing goods and belonging to any industry begin their manufacturing by making the bill of materials (BOM) for that particular product. The engineering department makes an engineering bill of materials (EBOMS), whereas the product team relies on the manufacturing bill of materials (MBOMS).
Accordingly, the following teams use a BOM-
The Bill of Materials (BOM) contains the details about the particular product’s engineering, design, document management, manufacturing, purchasing, contract manufacturers, etc. There could be certain custom information based on the product. Such information may include mechanical or hardware-related, electrical (e.g., ICs, PCBAs), or software-related information. More commonly, the following is the list of particulars in a typical Bill of Materials (BOM)-
A single-level structure of BOM depicts the assembly and subassembly once or at one level with the required quantity. Whereas a multi-level structure of BOM depicts a further indented view of parent and child parts or assemblies needed to build the product along with the quantities.
For example, below are the two varieties of BOM of an office chair.
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There are several classifications of bills of materials. However, the two most critical and popular BOMs used for purchasing and supply chain management are the Engineering Bill of Materials (EBOM) and the Manufacturing Bill of Materials (MBOM).
The use of BOM varies based on the project under consideration and the requirements of the enterprises. The types of BOMs used in the manufacturing industry include the following:
A high level of accuracy is expected for a BOM. A custom manufacturer must mention all possible details in the BOM to ensure efficiency in the production process. Therefore, creating the bill of materials is one of the steps in the product development process.
A final bill of materials is created after several iterations and involves several teams. While the spreadsheet is one of the modes to create a BOM, using an ERP system is the best solution for effective BOM management. Spreadsheets are prone to human errors, and version or revision tracking among various teams in the organisation becomes difficult. Whereas a future-proof cloud-based system ensures the availability of the latest version to the entire organisation.
Using an ERP system also has multiple advantages due to integrating teams and collaborating for faster processing. It enables centralised control of the entire product record and ensures delivery of a superior quality product. It allows easy procurement of parts and other teams to plan well ahead of time. Hence, an ERP system is the best possible solution for effective and efficient BOM management.
BOM requires continuous monitoring throughout the lifecycle. Hence, it requires frequent reviews and revisions to deliver a quality result.