Bill of Materials (BOM), or structure, is a list of all the parts needed to build the end product. Parts include discrete components, sub-assemblies, raw materials, firmware and labor.
Bill of Materials can be hierarchical or flat. A hierarchical BOM displays a multi-level view of sub-assemblies and reusable blocks, used to build the product, whereas a flat BOM, displays a consolidated list where every line represents a unique item.
For eg: the simplistic view of a smartphone BOM would include Display/touchscreen, Memory, Sensors, camera module, WLAN/Bluetooth module, screws, fasteners etc. The camera module could be further exploded into the lens, the processor, the embedded firmware, camera mount etc.
Parts within a BOM are represented using their Part numbers and other properties that best describe the part.
Engineering BOM, or EBOM, or sometimes referred to as design BOM, is a list of items that defines the design of the end product. They are usually generated from a CAD (Computer Aided Design) or PCB (Printed Circuit Board) or other design software. They contain the engineering specs of the components, for eg: tolerance, operating temperature, weight, unit of measure, dimensions etc.
The end product can be a combined list of one of more EBOMs.
Manufacturing BOMs or MBOMs define the list of items required to build the product that can be shipped to the customer. This includes the packaging materials (box, labels etc), Help manuals as well as assembly instructions and manufacturing processes.
Another big difference between EBOM and MBOM is the way they’re structured. EBOMs are often structured the way the engineers designed the product. For eg: all the parts comprising the camera module, may be listed under a line item called ‘camera module’.
However, an MBOM is often structured based on how the products should be manufactured. In the previous example, let’s assume the plant consists of 2 machines that can assemble items from the engineering BOM, using different processes.
Using a Bill of Materials software to manage BOMs brings several benefits to product teams. Excel is still a very common tool used to manage BOMs. Managing BOMs in Excel may appear simple, but have several pitfalls, discussed in detail in another blog. Here’s a comparison between Excel and FusePLM’s Bill of Materials software capabilities.
| Excel BOM |
FusePLM BOM |
| Data entry errors with copy/pasting data |
Cloud-based database maintains links between the end product and underlying objects |
| Tedious to setup Hierarchical (multi-level BOMs) |
Easily setup flat or indented hierarchical BOMs. |
| BOM Revisioning is accomplished by renaming Excel files (*V1.xlsx, *V2.xlsx etc.) |
Manage major/minor revisions of any part/BOM, compare and track changes to revisions |
| Documents cannot be managed 'within' the Excel BOM |
Manage specifications, assembly instructions, design files within the 'BOM' record. Improve traceability. |
| Cost and Quantity rollup calculations complicated to setup in Hierarchical BOMs |
Built-in cost and quantity rollup calculations at any level of hierarchy. Switch cost values to perform what-if cost analysis. |
| Collaboration with team members done at file level. No workflows to control access to changes. |
Powerful, yet easy-to-setup workflows to control changes to BOMs. Understand what changed, who changed it and when it was changed. |
FusePLM’s Bill of Materials software provides the following benefits:
- Manage all the properties defining your parts/BOMs in one location
- Manage the supply chain information for BOM items, including Approved Manufacturer Lists (AML) / Approved Vendor Lists (AVL)
- Multiple views of the BOMs – hierarchical and flat
- Maintains complete audit trail of changes to parts/BOMs
- Traces what BOMs get impacted due to change in parts
- Automatic Cost and Quantity Rollup calculations. Perform what-ifs costing analysis at BOM level
- Easy Excel/CSV Import and Export
- Control read/write access to parts/BOMs for internal and external customers.
To learn more about FusePLM’s capabilities, click here.
