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…
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.