When To Divide A Manufactured Part Into Sub Parts

Cetec ERP’s flexible build process lets you structure your manufacturing process to fit your needs, including the creation of complex multi-level Bill Of Materials (multi-level BOMs).

For example, if we are building a boat, we could create a single BOM for a boat, with the engine, shell, and wheel house all contained within a single part. Alternatively, we could separate the build processes for the engine, the shell, and the wheel house, and then assemble them into one final boat build process. Both structures are valid, and both will let you build a working boat at the end of the day. But one may be better suited to your needs than another.

If any of the pieces in the build will ever be overbuilt, or stored on stock apart from the top level, then you will want to create a separate BOM structure, i.e. a sub-assembly, for the part. In many cases, set-up time to build a piece is high enough that building more than is needed for a specific job is prudent - controlling that piece of the build as a separate sub-assembly lets you easily overbuild and reduce the impact of the set-up. Additionally, if the sub-assembly is common to several builds, then structuring it as a shared component provides more flexibility and control to the build process.

That said, if the above factors aren’t present, then leave the build alone and keep your top-level BOM completely flat. The overhead and complexity associated with dividing a manufactured/assembled part into several sub pieces with respective distinct BOM records should be avoided unless there is a specific benefit to managing them as separate.