The dilemma for Bill of Materials (BOM) management arises due to conflicting perspectives on how to structure and manage BOMs effectively. There are two primary viewpoints that contribute to this dilemma:

  1. Modular BOM Perspective: From a modular perspective, BOM management involves organizing assemblies and subassemblies in a hierarchical structure. This approach recognizes that products are often built using modular components and subassemblies. Each module or subassembly is treated as a separate entity, allowing for easier management, reuse, and maintenance. This perspective emphasizes the modularity and reconfigurability of products, enabling efficient design changes and customization.
  2. Whole BOM Perspective: on the other hand, the whole BOM perspective considers the BOM as a cohesive whole, where each component is treated as an individual entity, regardless of its position within the assembly hierarchy. This viewpoint emphasizes the need to manage and track each component independently, ensuring accurate documentation, procurement, and inventory management. It focuses on the individual components’ specifications, lifecycle, and dependencies, without considering the assembly structure explicitly.

The dilemma arises because these two perspectives have different priorities and implications for BOM management:

  • Complexity vs. Simplification: The modular BOM perspective aims to simplify the management of complex products by breaking them down into modular components. This approach enables better control over changes, promotes reuse, and supports concurrent engineering. However, it may introduce additional complexity in managing relationships between different modules and subassemblies.
  • Granularity vs. aggregation: The entire BOM perspective emphasizes granularity, treating each component independently to capture its specific characteristics, life cycle, absolute position in the product… This approach ensures tracking and precise management of components, allows to track a component in different product views (engineering BOM, manufacturing BOM, service BOM), to manage BOM filtering (extract all components that are within 20 cm of a given component). However, it can ignore relationships and dependencies between components, potentially missing the big picture of how they fit together to form assemblies.
  • Product Structure Engine implemented in PLM software: some PLM software only supports the simple « assembly – component » relationship, and do not allow a component to be explicitly referenced independently of its position in the product structure tree

The key to resolving this dilemma lies in finding the right balance between the two perspectives. Effective BOM management requires considering both the modular structure of assemblies and subassemblies and the individual characteristics and lifecycle of each component. This can be achieved through advanced PLM systems that allow for hierarchical representation of assemblies while maintaining comprehensive component-level data. These systems enable organizations to navigate the complexities of BOM management, facilitate efficient collaboration, and ensure accurate and up-to-date information across all levels of the BOM hierarchy.