Visit Bill of Materials (BOM) is a structured, hierarchical document that exhaustively lists all the components, sub-assemblies, raw parts and raw materials needed to manufacture a finished product, including the exact quantities required.
In-depth definition : Nomenclature is, in the literal sense, the manufacturing recipe of the product. It is created during the’Industrialisation by the design office or Methods and is a key part of the Manufacturing file. Its tree structure (often referred to as “BOM explosion”) defines the parent-child relationships between the different assembly levels. Its accuracy is vital, as the slightest error in quantities or part numbers has a direct impact on costing, purchasing planning and production efficiency by Series Production.
BOM's Essential Functions for Industrial Performance
For the’Operational Excellence and the Industrial Engineering, The BOM is a multifunctional tool and a critical control point:
A. Planning and Logistics (MRP)
- Material Requirements Planning (MRP) : The BOM is the fundamental input to the system MRP (Material Requirements Planning). MRP uses the BOM to “break down” demand for finished products into all the necessary components and raw materials, thus determining precisely what needs to be purchased or manufactured in-house, and when.
- Inventory management : It is essential for tracking inventory movements and assessing the cost of work-in-progress (WIP) and finished products in the’ERP (Enterprise Resource Planning). A fair BOM is the condition sine qua non to avoid waste (Muda) due to overstocking or breakage.
B. Costs and Finance
- Calculating the Cost of Goods Sold : The BOM is used in finance to calculate the standard theoretical cost of a product. By multiplying the quantity of each component by its unit cost, we obtain the material value of the finished product. KPI essential for operating margin.
- Cost control : Analysis of the BOM enables Industrial Engineering identify expensive components and work on simplifying them (using the DFMA - Design for Manufacturing and Assembly) or reducing their quantity.
C. Execution and Quality (MES)
- Assembly instructions : It is the basis for all Work Instructions and kit preparation lists. It ensures that the right component is used in the right place at the right stage of the process. Manufacturing range.
- Traceability : Each line in the BOM is linked to a unique reference, enabling traceability of the component throughout the entire product life cycle, in particular via the MES (Manufacturing Execution System).
The different types of nomenclature
Depending on the product's function or point in its life cycle, a distinction is made between :
- Engineering BOM (EBOM) : Reflects product design as defined by R&D.
- Manufacturing BOM (MBOM) : Represents the structure of the product as it is actually manufactured. It includes consumables (glues, paint), temporary assembly subassemblies and the way in which the Manufacturing range uses the components. It is the MBOM that is used by the MY.
- Sales BOM (SBOM) : Describes the final product as the customer receives it, often used for configurable products with different options.
BOM and Digital Transformation (Industry 4.0)
In an environment of Industrial Digitization, the BOM is a dynamic element:
- Electronic management : It is managed by a PLM (Product Lifecycle Management) or directly in the’ERP, ensuring that only the most up-to-date version (often linked to a Digital Twin of the product) is used by the production and purchasing departments.
- Variant complexity : Digital tools make it possible to manage the complexity of ultra-customized products (wide variety of part numbers) using modular BOMs and automatic configuration rules.
In conclusion, the Parts list is the foundation of the company's technical data. Its rigor is the expression of maturity in Industrial Engineering of an organization. Ensuring its accuracy is the first step towards efficient, cost-effective planning and execution.