Bill of Materials, a.k.a. BoM
What is a BoM?
Bill of Material, in its simplest form, can be described as a list of parts that are needed to build an end item, a.k.a the End product. And by part, we mean all the materials required for making a part. If your SS316 bolt is painted in bright Red color, then the SS316 bolt, the Red color, and the auxiliary tools to do the painting, you need to keep an account of all the things that are needed to make your final product. A Bill of Materials (BOM) is a comprehensive list that details all the components, parts, and materials required to manufacture a product. It serves as a blueprint for production, guiding the assembly process.
Why do we need BoM?
Whether you are building a frugal skateboard or a multi-million spacecraft, you need to have a list of things and a sequence of arranging those things to make a usable end product that serves a function. The part list serves a crucial role but can only help you to an extent. If you are building a complex product with a lot of components, what you need is a fancy version of Part List that can help you and your team understand the type, quantity, material, EAU, Cost, ..basically any metadata that is crucial to your business process marked against each row of your part list. Add to that features like an auto roll-up of similar parts till immediate or at the end product level to derive insights about EAU or the carbon footprint that your product is causing.
The BOM provides a structured framework for collaboration among different departments, such as engineering, procurement, and production. It ensures consistency, accuracy, and traceability throughout the manufacturing process, facilitating efficient production and maintenance of products.
Accurate Ordering: The BOM ensures that the correct quantities of components are ordered. This eliminates the risk of shortages or excess inventory.
Quality Control: The BOM specifies the type and specifications of each component, ensuring that only approved materials are used. This helps maintain consistent quality and avoids rework.
Assembly Instructions: The BOM can include assembly instructions, ensuring that the components are put together correctly. This reduces the likelihood of mistakes or improper assembly, minimizing the need for rework.
Cost Estimation: The BOM provides a clear breakdown of the materials required, allowing for accurate cost estimation. This helps in budgeting, negotiating prices with suppliers, and identifying potential cost-saving opportunities.
How do we prepare BoM?
The most common industry practice is to start with creating a rough BOM structure using your CAD structure (based on your CAD model) and then add non-CAD items as you move forward. But, in theory, you don’t need a CAD model to make a BOM. I say in all my conversations that MS Excel was, is, and will remain the number one BOM tool used in the industry. As mentioned in the example above, the Bolt, the paint will show up as part of the material list, but the process of painting too can be mentioned against them, integrating your Bill of Process into your Bill of Material. Depending upon your process and needs, you can see the BOM in an indented multi-level parent-child nested view, or you can view it in a more global flat list kind of view where the system will ignore the detailed parent-child relation and instead aggregate the qty of similar parts directly under the root parent.
Types (a.k.a. Views) of BoM? (not an exhaustive list)
Engineering View (eBOM)
Planning View (pBOM)
Manufacturing View (mBOM)
Service View (sBOM)
Typically, advanced BOM solutions also give the users the flexibility to view the BOM from various perspectives. For example, someone in the engineering dept may want to see the BOM from a ‘Work in Progress’ perspective, but at the same time, someone else from the purchase dept may want to see the very same BOM from an ‘As Latest Released’ perspective where he will see only the latest released data on which he can go ahead and raise purchase orders.
Where do we use BoM?
Everywhere! Even if you are not using some fancy expensive software, you are still incorporating the fundamentals of BOM in your daily life. Imagine something as simple as assembling and then sequentially using items to cook a meal. Any place or domain where you need to conceptualize, design, make/buy and assemble a product is a potential place to use BOM. From Lego toys to International Space Station and everything in between, all the industries making all sorts of things utilize some or other form of BOM to design and make awesome things all over the world (and beyond!).
