Bill of Materials (BOM)

A list of the components and materials needed to assemble a product.

Also called: Parts List, Assembly List, Parts Breakdown, Parts Catalog, Parts and Materials List, Product Structure, Product Tree, and Product Hierarchy

Relevant metrics: Cost of Materials, Quality of Materials, Availability of Materials, Lead Time of Materials, and Supplier Reliability

In this article

What is a Bill of Materials?

A Bill of Materials (BOM) is a comprehensive list of components, assemblies, and other materials required to construct, manufacture, or repair a product or service. It is a critical document in product management and user experience, as it provides a detailed overview of the product’s components and their relationships.

A BOM typically includes the item number, description, quantity, and unit of measure for each component. It may also include the supplier, cost, and other relevant information. The BOM is used to track the components of a product, as well as to ensure that the product is built correctly and to specification. It is also used to track the cost of the product, as well as to ensure that the product is built in a timely manner.

The Bill of Materials can serve as a roadmap of the components and technologies needed to develop a specific software or hardware product, including specifications and quantities of each item. BOMs help to ensure that all necessary materials and resources are available and accounted for during the development process, and can also aid in project planning, cost estimation, and supply chain management.

A BOM is typically organized into a hierarchical structure, with the top-level item being the product itself. The components of the product are then listed in descending order, with the lowest-level components being the most basic components. This hierarchical structure allows for easy tracking of the components and their relationships.

Where did term “Bill of Materials” come from?

The term Bill of Materials (BOM) has its origins in the manufacturing industry. It is a document that lists all the components, parts, and materials required to build a product. The BOM is used to track the cost of the product and to ensure that all the necessary components are available for production.

The term was first used in the early 1900s when manufacturers began to use the document to keep track of the parts and materials needed to build their products. The BOM has since become an essential tool in the manufacturing industry, and is used to ensure that all the necessary components are available for production.

Essential concept for complex manufacturing projects

A BOM is a critical tool for any manufacturing project, as it helps to ensure that all the necessary components are available and accounted for during the manufacturing process. It also helps to ensure that the product is built to the highest quality standards. The BOM also helps to identify any potential problems that may arise during the manufacturing process, allowing for quick resolution.

The BOM is also used to track the progress of the manufacturing process. It can be used to monitor the progress of the project, as well as to identify any potential problems that may arise. This helps to ensure that the project is completed on time and to the highest quality standards.

The BOM is also used to track the cost of the project. It can be used to identify any potential cost savings that may be available, as well as to identify any potential cost overruns. This helps to ensure that the project is completed within budget.

Why apply the concept of a Bill of Materials?

A BOM should include a comprehensive list of all hardware and software components necessary for a product, along with detailed specifications of each component as well as the quantity of each component required for the project.

With the detailed specifications and quantities of all components in hand, project managers can effectively plan their development timeline and budget accordingly. The BOM can also be used to identify any potential supply chain issues early on, allowing for quick resolution and minimizing delays.

By monitoring and tracking components through the supply chain, project managers can ensure that all necessary materials and resources are available when required. This helps to avoid any disruptions in the development process and keeps the project on track.

By providing a shared understanding of all components and resources required, it’s easier for teams to work together towards a common goal.

The document should be regularly updated to reflect any changes in the development process. This helps to ensure that all team members have access to the most up-to-date information, and helps to minimize any potential misunderstandings or miscommunications.

Types of BOMs

Not all BOMs are created equal, and understanding the different types of BOMs is critical to selecting the right one for your needs.

Engineering BOM. The Engineering BOM is typically created during the design phase of a project. It includes detailed information about the design, specifications, and materials required to build the product. The Engineering BOM is used to validate that the design meets the requirements and can be manufactured within budget.
Manufacturing BOM. The Manufacturing BOM is a list of the parts and materials required to manufacture the product. It is typically used by the production team and includes information on quantities, suppliers, and part numbers. The Manufacturing BOM is also used to create production schedules and identify any potential production issues.
Component BOM. The Component BOM is a list of all the components required to build a product, including subassemblies and raw materials. It provides a comprehensive overview of all the materials required to manufacture a product and is used to manage the supply chain.
As-Built BOM. The As-Built BOM is a record of the final configuration of a product. It includes all the components and materials used to manufacture the product, including any changes made during the production process. The As-Built BOM is used to maintain a record of the product’s configuration for future reference.

The type of BOM used in product development will depend on the specific requirements of the project. Engineering BOMs are typically used during the design phase, while Manufacturing BOMs are used during the production phase. Component BOMs are used to manage the supply chain, and As-Built BOMs are used to maintain a record of the final product configuration.

Advantages of Implementing a Bill of Materials

Enhanced Quality Control. A BOM helps to ensure that the right components are used in the right quantities, which helps to ensure that the product is of the highest quality. This helps to reduce the risk of defects and improve customer satisfaction.
Improved Traceability. A BOM also provides a record of all the components used in the production process, which can be used to trace any issues that may arise. This helps to ensure that any problems can be quickly identified and addressed, reducing the risk of costly delays or product recalls.
Increased Visibility. A BOM also provides visibility into the production process, allowing for better planning and forecasting. This helps to ensure that the right components are available when needed, reducing the risk of delays or shortages.

Challenges of Implementing a Bill of Materials

Applicable for digital product development? It is fair to question whether the concept of Bill of Matererials relates fully to digital product development. However, if you’re working in a software/hardware setting, you will have to deal with this concept one way or the other.
Accurately tracking inventory. A Bill of Materials requires accurate tracking of inventory, which can be difficult to maintain if the inventory is constantly changing.
Ensuring accuracy of data. A Bill of Materials requires accurate data to be entered into the system, which can be difficult to ensure if the data is coming from multiple sources.
Keeping up with changes. A Bill of Materials must be updated regularly to reflect any changes in the materials used in the production process, which can be time-consuming and difficult to manage.
Integrating with other systems. A Bill of Materials must be integrated with other systems, such as accounting and inventory management, which can be challenging to do.
Ensuring compliance. A Bill of Materials must be compliant with industry regulations, which can be difficult to ensure.

What is in a Bill of Materials?

A BOM typically includes the following information:

Part number
Description
Quantity
Unit of measure
Cost
Supplier
Manufacturer
Assembly instructions

A BOM can be created manually or with the help of software. Many companies use software to create and manage their BOMs. This helps to ensure accuracy and consistency across all products.

Relevant questions to ask

What is the purpose of the Bill of Materials?
Hint The purpose of the Bill of Materials is to provide a comprehensive list of all the components, parts, and materials needed to create a product or complete a project.
What items will be included in the Bill of Materials?
Hint Items included in the Bill of Materials typically include raw materials, components, parts, assemblies, and sub-assemblies.
What is the expected timeline for completion of the Bill of Materials?
Hint The expected timeline for completion of the Bill of Materials will depend on the complexity of the project and the availability of the necessary components and materials.
What is the expected cost of the Bill of Materials?
Hint The expected cost of the Bill of Materials will depend on the cost of the components and materials needed to complete the project.
What is the expected quality of the Bill of Materials?
Hint The expected quality of the Bill of Materials will depend on the quality of the components and materials used.
What are the legal implications of the Bill of Materials?
Hint The legal implications of the Bill of Materials will depend on the laws and regulations applicable to the project.
What are the potential risks associated with the Bill of Materials?
Hint Potential risks associated with the Bill of Materials include incorrect or incomplete information, incorrect or missing components, and incorrect or missing materials.
What are the potential benefits of the Bill of Materials?
Hint Potential benefits of the Bill of Materials include improved accuracy, improved efficiency, and improved cost savings.
How will the Bill of Materials be maintained and updated?
Hint The Bill of Materials will be maintained and updated by the project manager or other designated personnel.
Who will be responsible for the accuracy of the Bill of Materials?
Hint The project manager or other designated personnel will be responsible for the accuracy of the Bill of Materials.

People who talk about the topic of Bill of Materials (BOM) on Twitter

Johnathan O'Keeffe @johnathanokeeffe
Chris Gledhill @cgledhill
Paul Myerson @paulmyerson
Mark Boulton @markboulton
Steve Banker @stevebanker

Relevant books on the topic of Bill of Materials (BOM)

Product Design and Development, 5th Edition by Michael Grieves (2018)
Design for Manufacturability and Statistical Design: How to Use Quality Engineering to Lower Costs and Improve Quality by David M. Anderson (2017)
Design for Six Sigma: A Roadmap for Product Development by David M. Anderson (2003)
Design for Lean Six Sigma: A Holistic Approach to Design and Innovation by David M. Anderson (2011)
Design for Reliability: A Strategy for Product Development by David M. Anderson (2009)

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