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Who Prepares the Bill of Materials?

A bill of materials is a centralized source of information that allows multiple teams from design, engineering, and manufacturing to collaborate. It includes all of the components and raw materials needed to build a product.

A BOM may be single- or multi-level, and it can be based on components, raw materials, sub-assemblies, or assemblies. It also indicates the units of measurement and how to procure parts.


The BOM (Bill of Materials) is a crucial part of the product development process. It lists all raw items and assemblies needed for a final product. It provides a detailed picture of the entire project and allows engineers to handle all operational aspects of the production process. BOMs also help companies reduce costs and increase their brand’s quality. There are many different types of BOMs, but the best one for your company will depend on the type of product you manufacture. In this blog post, we will talk about the definition of BOM, its various types, and structures, as well as steps on how to prepare it.

An engineering bill of materials, also known as an EBOM, is a special type of BOM that defines the design of a finished product. It includes alternative and substitute part numbers, drawing notes, and other important data. This data is essential for manufacturing and supply chain teams. It also ensures that the final product is designed exactly as intended and makes it easier to ramp up tools and launch production runs.

A manufacturing bill of materials, or MBOM, is a subset of the EBOM that details what is needed to assemble the final product. The MBOM is an extremely valuable tool that helps manufacturers plan purchases, estimate cost, control inventory, minimize production delays and maximize efficiency. It also enables engineers to quickly identify the source of a failure and work to resolve it.

It is essential to create an accurate and thorough BOM. Inaccurate or incomplete BOMs can lead to inaccurate product costs, errors in the assembly process, inventory inaccuracies, and costly production delays. These problems can be easily avoided with an effective BOM management system.

A complete and accurate engineering BOM enables engineers to release their designs for manufacturing without any last-minute changes. This allows the engineers to get their products into production faster and make them available to customers more rapidly. The EBOM also enables manufacturing and supply chain teams to make better decisions, including pricing and lead time options, manufacturing process choices, and logistics and shipping choices.


A bill of materials (BOM) is a comprehensive list of the raw materials, assemblies, sub-assemblies, components and parts that are required to manufacture a specific product. It also lists their quantity needed to make a finished product. It is a crucial document that helps to ensure that all the components and materials are available in sufficient quantities for assembly. It also serves as an important tool for controlling production costs and minimizing waste.

BOMs can be categorized into different types based on their purpose and level of detail. For example, an engineering bill of materials includes a detailed breakdown of component parts and their suppliers. This information can be shared with development, management and production planning teams to give them a good idea of how complex and expensive the product will be. This is a good way to keep track of the costs and complexity of a new product while it is in the development stage.

Once the engineering phase is complete, the BOM can be rolled over to the manufacturing department. This will produce a new manufacturing BOM, which will contain the necessary components and materials for manufacturing a finished product. This will allow the manufacturing department to track the status of each assembly and sub-assembly, as well as their supplier locations. A manufacturing BOM can also help to identify any issues that might occur during the assembly process.

A typical manufacturing BOM is a hierarchical structure that includes components, assemblies and sub-assemblies. It contains a number of vital details about each part, including its unique code, description, lifecycle status and approval status. It may also include a reference designator, which specifies where each part fits on a printed circuit board (PCB) or other assembly. It can also have a barcode or other identification system.

Depending on the type of product, the BOM might also include information about labour costs, like the time it takes to assemble or manufacture each component. This information can be incorporated into the manufacturing cost estimate and used to make purchasing decisions.

The format of a BOM varies per industry and company, but most have a similar structure. It should include the name of each component, their quantity and a unit of measurement, such as pounds or kilograms. It should also include the supplier contact information, a reference designator and the manufacturing processes. Moreover, it should be updated regularly to reflect the changes in manufacturing techniques or materials.


A bill of materials is a critical part of the engineering and manufacturing process. It consists of the raw items and equipment required to construct or manufacture a product. A BOM can be used to reduce waste, streamline production, and ensure the quality of the final product. It can also help companies manage their operational costs. There are many different types of BOMs, and each one has its own purpose.

Whether you’re using SLS 3D printing or injection molding to build your products, a well-defined and structured production management process is crucial for the success of your projects. A BOM is a central repository for all your project data, and it should be used by teams across the company to communicate with suppliers. A good BOM should also include a detailed description of each component, including its unique code, cost, lifecycle status, and approval information. It should also include the minimum order quantity (MOQ) and vendor information.

The main purpose of a BOM is to ensure that all components are available when needed. It also helps the production team understand which items are needed for a particular assembly task. It can be presented in a variety of formats, including flowcharts and tables. It should also include a unique part number and description for each item, as well as the required quantity. It can also be broken down into sub-assemblies and subcomponents.

BOMs are often used as the primary source of data for various business processes, including material requirements planning and ERP systems. Typically, the BOM is a leveled, hierarchical list with crucial information about each part or assembly, such as its unique code, description, lifecycle status, and approval history. It can also display additional specifications such as color, size, or material.

The BOM impacts multiple departments throughout the product development cycle, from the initial concept phase to the finished and shipped product. It evolves from an initial list to an EBOM, MBOM, or SBOM as the engineering and manufacturing process unfolds. An EBOM, or engineering bill of materials, defines the assembly structure from a functional perspective and is created by engineers using CAD tools. A MBOM, or manufacturing bill of materials, specifies the raw materials and assemblies that are needed to produce a finished product.


The bill of materials is a centralized source of information that allows manufacturing teams to make informed decisions and minimize waste. It identifies the components and sub-assemblies needed to build a finished product, including their locations and quantities. The BOM can be presented in a number of formats, depending on the industry and purpose for which it is being used. For example, scaffolding companies use a BOM to ensure they have all the parts and components required to construct a scaffold before sending it out for service or construction. In addition, it also helps to reduce the risk of inventory inaccuracies and construction delays.

There are different types of bills of materials, and each type serves a unique function in the manufacturing process. Typically, the engineering BOM is created by engineers during the design phase and contains all of the components for the finished product. This BOM includes all of the raw materials and finished products, as well as any tools and equipment needed to produce them. It is usually formatted in a hierarchical way, with the parent-level items appearing at the top of the list and all of the child-level items following. This format is often referred to as an indented BOM.

A multi-level bill of material (MBOM) is similar to an engineering BOM but is more detailed and includes the parts and sub-elements that make up a higher-level assembly. The format of the MBOM is similar to an indented BOM, but it also contains part numbers and descriptions, as well as quantity details. Creating a multi-level bill of material is an essential step in the product development process and can help prevent costly errors.

Another type of bill of materials is a building services or contract BOM, which lists the work and materials needed to complete a construction project. This type of bill of materials is useful for comparing contractor proposals. It can help avoid misunderstandings between the contractor and the project manager, as it provides a standard scope of work that can be referenced. The contractor’s proposal can then be compared against the contract BOM to determine the most competitive price.