What Is LN Bill of Material?

LN Bill of Material Explained

LN stores bills of material one level at a time: a parent item and its immediate components. Multi-level structures emerge because a component can itself be a manufactured item with its own bill. The system explodes through those levels when it needs to, for planning, for costing and when creating production order material lines, which keeps maintenance local - changing a subassembly automatically affects every parent that uses it.

Each line carries more than an item and a quantity. Position numbers identify the line stably for engineering change purposes. Net quantity and scrap or yield factors distinguish what the product contains from what must be issued to build it. Effective from and to dates control when a line is valid, which is how engineering changes are phased in without deleting history. Where a routing exists, the operation number ties the component to the step that consumes it, so material is issued at the right point rather than all at order release.

Phantom items are the structural trick worth understanding. A phantom is a subassembly that exists in the engineering structure but is not built and stocked separately; when planning explodes the bill, it passes straight through the phantom to its components. This lets engineering keep a logical structure while manufacturing avoids creating and transacting an item that never sits on a shelf. Misclassified phantoms are a recurring source of confusing planning results.

The bill also drives cost. Standard cost calculation rolls component costs up through the structure, applying cost components at each level so the finished item's cost can still be decomposed into material, operation and overhead. For configurable products, generic bills of material work with the product configurator to generate a structure per configured order rather than maintaining a separate bill for every possible variant.