Multi-level and nested BOMs

A multi-level BOM is a bill of materials whose components are themselves manufactured items with their own BOMs. This lets you model products that build up in stages.

How nesting works

When a component on a BOM is itself a made item, that component carries its own BOM. The result is a tree: the finished product sits at the top, sub-assemblies in the middle, and raw materials at the bottom.

Build a nested BOM

1. Create a BOM for each sub-assembly first.
2. Open the parent product’s BOM in the master BOM editor.
3. Add the sub-assembly as a component line, just like any other item.
4. Fiddle marks it as a made item and links to its underlying BOM.

How it expands on a work order

When you raise a work order for the top-level product, Fiddle expands the full tree and scales every quantity to the build amount.

Level	Example	Built by
Top product	Gift box	A work order
Sub-assembly	Candle	Its own work order
Raw material	Wax, wick	Purchased stock

Sub-assemblies must be in stock to consume them. Either build them on their own work orders first, or use assemblies to produce them as part of the parent build.

Next steps

Learn how to produce intermediate items with assemblies and sub-assemblies.