Variation may drive sales, but fully customizing each product sold destroys profitability. Delivering a product with variations to the marketplace relies on a foundation of modular product designs, Bill of Material (BOM) management, and the ability of production processes to handle deviation. Manufacturers recognize that product variants or multiple product configurations, managed with the proper tools during engineering and production, are critical to their business success.

Multiple configuration products include not only “part families” that vary solely in dimension, but more importantly, products that include both functional and cosmetic differences. Aerospace manufacturers deliver both standard and elongated commercial passenger configurations of their airplanes, as well as cargo freighter and military variations. In automotive, vendors flood the market with customer-selectable options, including engine size, in order to entice their buyers.

The same holds true in the high tech electronics, industrial machinery, and medical devices industries.
BOM management of product designs impacts the full range of Product Lifecycle Management (PLM) domains from engineering to sourcing, manufacturing, and service. The proper product definitions organized around the multiple configurations of the product, together with strong BOM management tools to visualize, control, and change those configurations, provide leading edge manufacturers with valuable ammunition to compete more effectively.

The market is now hyper-sensitive to quality, both in reality and perception. It takes only one stumble to call into question years of a company’s hard fought reputation for quality. Every product manufacturing company drives relentlessly to improve and protect their quality record. Yet the pressure to deliver product variations and product options tuned to divergent customer demands is also increasing.

Product developers must carefully control requirements and dependencies across any number of product configurations or they risk introducing quality issues. Managing change during the product development process and analyzing its impact across product variants is central to that control.

BILL OF MATERIAL MANAGEMENT
The complexity and diversity of product engineering data alone forces the need to organize and structure that data. The resultant engineering Bill of Material (eBOM) represents design engineering’s definition of a product into a well defined and ordered hierarchy of objects. Each product subsystem, such as electrical, hydraulics, and mechanical, may require specific fields of information, its own data models, and a special view of the product structure.

As the eBOM moves through product development, additional data specific to manufacturing must be added. Even more challenging, the eBOM’s hierarchical BOM structure may need to change to better fit the needs of manufacturing and assembly processes. This creates a manufacturing Bill of Material (mBOM) that is the result of often complex data mappings between engineering objects and their realization in production.

The coordination of these potentially conflicting approaches between eBOM and mBOM must be supported in a coherent, overall product definition.

The leading manufacturers in industry verticals across aerospace and defense, automotive and transportation, large machinery, medical devices, and consumer products have reached the conclusion that their best practices centre on three key aspects for staging product development.

These three aspects center on a single source for product data, attention to process interactions that integrate different product silos, and the assurance that each contributor to the product development process access the correct data and tools to empower decision making.

THE NEED FOR SINGLE SOURCE MANAGEMENT
Product development leaders have grown to understand that a major eBOM best practice is to explicitly record the composition of multiple product configurations as a single source data structure and work with it to define and manage dependencies, requirements, and the effects of change. In this context, “single source” does not imply only one physical file or even one location of all the data.

Product variants are single source if any one product configuration “knows” of the existence of all other configurations and can access those differences when needed without human intervention. This contrasts with the traditional practices of using spreadsheets to structure product configurations, or defining all configuration options overlapping each other in a single database, where human intervention is required to define and separate the pieces of one valid configuration from another.

CPDA conducted an in-depth interview on the topic of BOM management for multiple configurations with Mike Christian, Teamcenter Mfg. CPAST Project Leader at Boeing Defense, Space and Security. Mike stated, “Our thinking starts with data models, whether they involve indentured BOM or flat product structure. Both play a huge role downstream. Based on capturing the configuration of a product, the entire bill, or a piece of the bill, we find that turning different things off in the COTS tool enhances that activity greatly. At Boeing we call it effectivity control. It is a key piece for us. Without that, we consider the data model as not configuration managed.”

Christian explained that without configuration management there was the potential to have flaws in downstream MES, MRP, or ERP systems that can cause shortages or overages (duplicate parts) and wasted time, effort, and component costs. He further added, “Searching abilities are also key. If we are looking for a specific subassembly within a giant assembly – and all the pieces in between – with a flat product structure we have a hard time doing that. People spend way too much time and manpower doing research, even on the shop floor.”

A strong BOM management tool should permit easy capture of the definitions of multiple product configurations, including the lifecycle status of its individual components throughout the full product development process. The tool can then allow audit of product information and provide visual feedback so that users can easily see the level of progress for each product component.

A proper BOM management solution can enable comparisons and verification of the configuration build status for testing, compliance reporting, and warranty verification. Most importantly, a strong BOM management tool enhances collaboration between individual contributors to the product development process, as well as between teams of contributors including supply chain partners.

PROCESS INTERACTION
The capture of eBOM and mBOM data for multiple product configurations provides the foundation for product developers to interact with their processes. Whether that process involves iterating the definitions of the product design between model designers and CAE simulation analysts to optimize the solution, or it relates to designers and manufacturing process planners in validating manufacturability, the managed BOM must not only integrate with a company’s processes, it should enhance those processes.

One vital process in product development across all industry verticals relates to change management. Being able to incorporate a product change as the product definition evolves and to assess the impact of that change across product variants and downstream operations is significant to assure smooth shop floor production.

On the topic of change management, Christian commented on Boeing’s use of the Siemens PLM Software’s Tecnomatix manufacturing solution: “The ability to visualize is a key point. At least with a BOM management tool, it is such a joy to see every piece, every aspect of the e-bill and m-bill. It changes everything. The basic flow-down of the product lifecycle from the very beginning is the solid model, and seeing the entire product. That includes handoffs between functions, including product support.”

He added, “Designers who looked at the BOM management solution say, ‘I like that I have the ability to see in that space so I can understand, so I can help myself downstream. Then when I have to make changes, I understand the build process.’”

EMPOWERMENT
The third major aspect of a strong BOM management solution relates to its ability to empower individuals who contribute to the new product development process and launch. The product data structures and content, together with a suite of BOM management tool functions for visualization, comparison, and control, all contribute to enhanced decision making. Enabling timely decisions based on accurate information moves a new product launch steadily forward to meet expected product release schedules.

Christian reinforced this aspect. “Process simulation and product simulation – those are key phases to manufacturability and producibility. We define that process to make sure the design is effective. We typically bring in the operators to do a virtual review of the design.”

He continued, “Decisions are made in an IPT (Integrated Product Team) environment, consisting of tool engineers, designers, manufacturing engineers, mechanics, and quality engineers converging on the solutions together. It is human intervention, but using the tools to help decide and define what you are looking at – whether it is a build process, a new design, or a change in flow. The tool enables the decisions.”

SUMMARY AND OPINION
Each product manufacturing company must decide for itself what products and product variants it will design and produce for their market. However, based on CPDA’s assessment of companies across numerous industry verticals, the most successful companies employ advanced BOM management tools to define and control their engineering and manufacturing efforts. Case after case of the product development process at manufacturers around the world, as Boeing testifies, shows that the use of BOM management tools is critical to success.

The proper BOM management tool enables PLM across the enterprise. Each of the three most recognized best practices for dealing with product variants – single source, process interactions, and empowerment in decision making – rely on a strong foundation in BOM management. As Mike Christian of Boeing Defense, Space and Security has affirmed, BOM management allows the capture, visualization, and manipulation of product data needed during the development cycle for multiple configuration products, and is vital to assessing a product’s “manufacturability and producibility.”

Ken Versprille is PLM Research Director, Collaborative Product Development Associates, LLC ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it ). This article originally appeared in the CPDA Tech Trends in PLM Update newsletter, September 2010.
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