How to avoid mistakes in Engineering BOM management

How to avoid mistakes in Engineering BOM management

My last week’s OpenBOM article How to Manage EBOM and MBOM () triggered a good discussion on LinkedIn and offline, which gave me the indication that the topic is far from conclusion. Check for comments on the LinkedIn article here. From my experience, there is no PLM implementation in the world that can avoid this topic.

It seems like no silver bullet. Depending on what the organization does and what system is using a different optimal organization of EBOM and MBOM structures and tools can be applied. The divide between EBOM and MBOM is created by data management practices, data organizations in a company.

In today’s article, I want to step back and talk about engineering BOM (EBOM), which by itself often causes many questions and sometimes creates confusion, unnecessarily complexity or conflict of interests in an organization.

The complexity of EBOM is caused by the architecture of CAD and PDM system as well as the data management practices. One of the myths about EBOM is that the concept was created with the invention of 3D CAD. Until 3D CAD (and especially mechanical CAD existed), the Bill of Materials was initially created on drawings and later the BOM of any organization was established in the MRP system. The later was a single BOM used by the organization to do everything. The growing complexity of products and product development processes contributed to the creation of EBOM as well as evolution PDM and PLM data management capabilities and best practices.

Engineering BOM process creation is a complex process allowing you to establish a single version of the truth about how a product is designed and also includes all information that manufacturing needed to start production planning as well as information needed to start purchasing and procurement process. EBOM is a single place where multi-disciplinary data about the product is managed.

Here are 3 common misconceptions that I found around the process of EBOM management.

1- Engineering BOM is managed in the CAD system

While the CAD system is a source of information for EBOM, the BOM is not created in the CAD system. The data from CAD systems are used to create a BOM, but the CAD system is far from ideal to manage EBOM. Therefore CAD and PDM (typically integrated with CAD) is not a good tool to manage EBOM. The root cause of misconception is that most CAD tools have BOM function. This BOM report is a starting point to create EBOM, but not engineering BOM itself.

2- Engineering BOM needs to be revision when you make CAD changes

CAD data management is a complex discipline. The core activity is design revisioning, which can be done manually or using PDM systems. Each time design is changing it leads to potential changes in the Bill of Materials. What is often not obvious is when these changes need to be applied to EBOM. The mistake is to think that every single change in CAD data needs to be applied to EBOM. The design changes might be different – design alternatives, reviews, and many others. EBOM management process should apply changes, but no way to be revised each time CAD documents are versioned.

3- All EBOM changes need to be synchronized back to CAD

Another point of confusion is to think about CAD data (files) as a storage for all information about EBOM. The root cause of the problem is bad EBOM management tools. Many organizations are still using Excel to manage EBOM. With a little trust in spreadsheets, organizations are using CAD file storage to keep data about EBOM. It causes a lot of complexity and redundancy. A robust PLM system capable to manage Bill of Materials is the right way to manage EBOM and avoid saving business data into CAD files.

What is my conclusion? Engineering BOM management is a foundation of product development processes. A system to manage EBOM creates a single version of truth for how the product is designed, possible configurations, options, non-model components, cost, initial information that needs to be later used for procurement and manufacturing. Engineering BOM data also can be connected not only to CAD systems but also to other tools used for functional and logic design, system engineering and many other disciplines. Once you’ve got the EBOM foundation in the right way, you have a better way to organize the data about the product and manage product development and manufacturing processes. Just my thoughts…

Best, Oleg

Disclaimer: I’m co-founder and CEO of OpenBOM developing cloud-based bill of materials and inventory management tool for manufacturing companies, hardware startups, and supply chain. My opinion can be unintentionally biased.

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  • Beppe UG Grimaldi

    Oleg,
    What do you think about 4GD?
    https://community.sw.siemens.com/s/article/learn-about-4th-generation-design
    that allow the CAD users to be isolated from the EBOM structure, creating it’s own desogn context?
    I’ve use it for a while and seems to be something that can help your vision of CAD vs EBOM.

    very hard to be sold to users that are very reluctant to abandon the “EBOM structure” in their CAD Assembly structure.

  • beyondplm

    Beppe,

    Great question and an interesting approach. I’ve seen the video earlier last year. I had no chance to use it first hand, but I think, the technology Siemens developed with the intent to solve traditional database management bottlenecks in hierarchies.

    It is hard to filter through the Siemens marketing in the video. What means different queries? Are those multiple indexes, databases or something else? It is not clear to me. However, the problem is well known – when you develop hierarchical queries, the performance will go down significantly with the product scale.

    In my own practice at openbom.com, we’re are solving similar problems of data management by applying polyglot persistence approach. OpenBOM is a multi-tenant structure. Even our single customer is relatively small (comparing to Siemens shipbuilding example), but the combined volume of tends of thousands of users and customers created a significant data set that is bigger than a single aircraft.

    PLM technologies should break the limits of a single SQL database – this is the only way to develop global engineering and manufacturing services for the 21st century.

    Just my thoughts…
    Oleg