Glossary · approach
Bill of Materials
The hierarchical tree that, at each level of a manufactured product, lists the immediate components and their quantities, recursively down to raw materials.
BOMParts ListProduct Structure
BOM (Bill of Materials) is the **hierarchical tree** that, at each level of a manufactured product, lists the immediate components and their quantities, recursively down to raw materials. It is the foundational data structure for MRP (#097), costing, engineering-change management, purchasing and assembly planning. Variants: single-level BOM (parent → direct children), multi-level / indented BOM (full recursive explosion), modular BOM (for configurable products), phantom BOM (an intermediate assembly that is never inventoried). Each parent-child relationship carries a quantity (children per parent), a scrap factor (production loss) and a yield factor (quality acceptance). Engineering-change management uses 'active BOM revisions': for the same part, an old revision may still be in production while a new revision has started; with an effective-from date, MRP explodes the correct revision. Source: Vollmann et al. (2005).
Örnek
BOM for a refrigerator: 1 refrigerator = 1 outer-case + 1 inner-cabinet + 1 compressor + 1 thermostat-module + 4 shelves. Thermostat-module = 1 PCB + 1 sensor + 0.5 m cable + 1 plastic-cover. PCB = 25 electronic components + 1 printed-circuit board. When a new model launches, the PCB drops from 25 to 22 components; engineering change order ECO-2024-187 revises the BOM; on effective-from 1 June, MRP switches to the new revision, and once the old PCB stock is depleted, production on the old revision stops.