Infor LN & BaanGlossary

What Is LN Bill of Material?

Also known as: LN BOM, bill of material LN, tibom

Definition

An LN bill of material is the parent-child list defining which components and quantities go into a manufactured item in Infor LN. Each line carries a position number, net quantity, scrap factor, effective dates and, optionally, the routing operation that consumes it.

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.

Why It Matters

  • Single-level storage with automatic explosion means a subassembly change propagates correctly without touching parent bills.
  • Effective dates are how engineering changes phase in without destroying the history needed for traceability and audits.
  • Operation-linked components control when material is issued, which changes shop floor inventory accuracy materially.
  • Standard cost accuracy depends entirely on bill accuracy, so BOM errors surface later as unexplained margin variance.

In Practice

A common trap is maintaining engineering and production bills as unconnected structures that drift apart. Manufacturing quietly corrects a quantity, engineering never learns, and the next revision reintroduces the error. Define one controlled transfer path from engineering data into the production bill, and treat any direct edit of the production structure as an exception requiring an engineering change.

Frequently Asked Questions

What is a phantom item in an LN bill of material?

A phantom is a subassembly that exists in the engineering structure but is never built or stocked as a separate item. When planning explodes the bill of material, it passes through the phantom directly to its components. This keeps the engineering structure logical while avoiding the transactions and inventory records for an assembly that only exists momentarily on the line.

How does LN handle engineering changes to a bill of material?

Bill of material lines carry effective from and to dates, so a change is phased in by ending one line and starting another rather than deleting history. Combined with position numbers and, where engineering data management is used, controlled revisions and change orders, this preserves an auditable record of what the product structure was on any given date.

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