Multi-level (or nested) BOMs usually raise many questions with users. In this article, I want to discuss how OpenBOM handles multi-level BOMs. And please keep in mind, we’re still working to improve how we handle multi-level BOMs. With that in mind, I’ll also share what multi-level related features we are still working on and what you can expect to be delivered in the near future. As I mentioned in the OpenBOM fundamentals (1) article, the simplest BOM is a list of parts. Each BOM contains [and can be assigned] Part Numbers; this is how you can identify items in OpenBOM.
By using Part Numbers in a BOM you can connect multiple BOMs together (nested levels) and it allows you to define multi-level BOM model. The Part Number, “z-stage” in the BOM, above, correspond to a sub-assembly in the top-level BOM:
Let’s now transition to Multi-level BOM navigation. The simplest, but not the most useful navigation of a multi-level BOM is using the “Composed of” button located in a BOM view. By clicking this button, you will navigate to the lower level BOM of a selected Part (if that Part happens to be assigned to a separate BOM). Otherwise, a “No nested BOM” message will appear. Our navigation to an upper-level BOM is not useful at the moment; we are working to improve it. The pic below shows where the “Composed of” button is located. When the part number “header assembly” is clicked, for example, “Composed of” will navigate you to the BOM with the Part Number, “header assembly”.
The Multi-level BOM view is a separate view available today as a Dashboard icon.
Although the multi-level BOM view is a separate view from the default single level BOM view, we are planning to improve this with future releases where single and multi-level views will be better integrated together and easier to navigate. With a multi-level BOM view, you can navigate between branches designated with a “+” in front of a number on the far left of the multi-level BOM. Note: Currently only one branch can be opened at a time.
In addition, you can configure what properties will be viewed in the multi-level BOM by clicking “View configuration“:
Here are videos that demonstrate multi-level BOMs in action:
All CAD plugins and Onshape provide support for generating multi-level BOMs