What is a bill of materials? A guide for medical devices

When you first embark on building a new piece of furniture, you’re usually holding a small booklet that outlines every part inside your box. Lining up your materials based on this list of parts ensures you have everything you need to make your desired product. If you’ve ever realized you're missing a part half way through your assembly project, you know just how vital an accurate list is to your end goal. When it comes to creating medical devices, this list of parts is known as a Bill of Materials (BOM). 

What is a bill of materials?

A BOM is a comprehensive list of raw materials and components needed to manufacture your final product. It outlines what raw materials or components to use and the quantities needed for each. A BOM helps with estimating costs, inventory management, reducing waste, and more. From sales to manufacturing, your BOM is a central guide for many departments within your company and is essential for making a medical device.

A BOM is usually a part of a Device Master Record (DMR). The DMR acts as a recipe for the device outlining how all the parts come together and are assembled to create the device.

Why do you need a bill of materials?

Without a bill of materials, you can’t clearly communicate to your manufacturing team what and how much material is needed for your device. If you’re using a contract manufacturing organization, not having a BOM means they can’t make suitable estimates on how much the project will cost. That, in turn, affects inventory control and could cause overbuying of a component. Or worse, a shortage in the supply chain right when you need to put out critical life-saving devices.

A BOM helps to give everyone an accurate picture of what’s needed to build your product. Your device needs the materials and components listed in the bill of materials—if something is missing, then you face potential defects and corrective action later in the process. 

When to create a bill of materials

You need to create a BOM as soon as possible—your team shouldn’t begin the production process without it. A bill of materials isn’t a one-and-done type of document, either. It should be a living document, updated as you proceed with making the device, and then edited when appropriate.

As you build your BOM, consider:

  • Who will manage it? Decide who is responsible for the BOM so that there are clear guidelines on who has the final say.
  • Who can access it? Determine editing and access privileges—it’s an important document, so you want to make sure only certain people have access. It helps if you can track any revisions that are made. Others may need to access it on a read-only basis.
  • How many types do you need? Figure out how many different types of BOMs you’ll need, as your BOM structure will change depending on the type. Setting up a template that you can refer back to for other new products could save you time in the long run.

Types of bills of materials

There are different types of BOMs that will be used to complete your medical devices. First, there are single-level BOMs. This type is the most simplistic and is usually just a list of assemblies/sub-assemblies, as well as how many of each part you’ll need. In a multi-level bill of materials, you get much more specific and build on that single-level bill of materials, addressing how every part is put together and listing every component of each part.

A multi-level BOM is hierarchical, so it displays your finished product at the top, then breaks that down into every component, including details such as cost, quantity needed, part number, descriptions of every part, and any other necessary details.

Other types of bills of materials include:

  • Assembly bill of materials: Parts needed to build out sub-components of the end product.
  • Engineering bill of materials: Shows how the product is designed, along with a list of every single part that goes into your medical device.
  • Sales bill of materials: List out finished products as well as any materials that can be ordered by a customer.
  • Manufacturing bill of materials: List each part’s name, how the parts are related to each other, their descriptions, as well as the quantities required.
  • Configurable bill of materials: Used for a product that requires configuration. Often, this is used when customers are able to request custom requirements, including anything to do with packaging or labeling.

The FDA is also looking at requiring a software bill of materials (SBOM) that outlines any third-party software components used in medical devices. They also want to add a cybersecurity bill of materials that would show any software that is potentially vulnerable. Currently, an SBOM is done on a voluntary basis, but it may be a good idea to start using it for premarket submissions. Since many medical devices already do use software, this is an area that med tech companies will want to pay attention to as new regulations take effect.

Maintaining your bill of materials

Your bill of materials is an important part of quality management—and without software to maintain it, it can become a momentous task to keep up with it. Electronic quality management software can automate many tasks associated with BOMs, like tracking changes and restricting edit access to those who need it.

Looking for an eQMS purpose built for medical device companies? Let’s talk about Qualio.