Why engineering Bill of Materials is complex

Why engineering Bill of Materials is complex


For the last year, I had chance to talk many manufacturing companies in range from small hardware startups to large manufacturing companies with billion dollar revenues and production facilities across the world.

I’ve learned that one simple question that can help you to understand all engineering and manufacturing processes in the company – Bill of Materials. By asking about BOM, you will be immediately exposed to a variety of topics that will tell you about how any company design, manufacture and service its products.

Brian Soaper’s article – Beginning BOM Management discussion reminded me many conversations about Bill of Materials I had with manufacturing companies. In this blog, I want to start from Engineering BOM. According to Brian, engineering is straightforward. Here is a passage from the article explaining that:

The engineering BOM is pretty straight forward and I think that many understand what it is and how it is used. However, I do get into conversations explaining how the CAD structure is different than the engineering BOM. I have seen companies with very detailed CAD structures where the non-geometric items are included (oil, tape, glue …). Other companies do not even model the fasteners in CAD. The majority of companies model only the geometric items. In the engineering BOM’s, they include the fasteners and other geometric items if they were not part of the CAD structure. I have found few companies that link the BOM items to the raw materials used to create them.

It made me think about 3 specific aspects of engineering BOM management I’ve observed. For the purpose of the conversation, let’s call them – Part List, Structures Transformation and Configurations. There is no canonic way to call them and I found the level of diversification is very high.

Part List. This is a simplest way to manage engineering BOM. Usually done by exporting information from CAD system and adding non-geometrical items. It is a very typical way to create a list that can be used for ordering purposes and /or communication with contractors.

Structure transformation. CAD structure is not engineering BOM. Restructuring is one of the most complicated processes to create engineering BOM. From my experience, this process can not be easy automated (if at all) and demand lot of human involvement. Mapping between structures is hard and to make references between two structures is even harder. But this is an absolutely important process to make engineering BOM right.

Configurations. Most of products today are demanding configurations – models, options, etc. Management of configurations in CAD system is complex and sometimes even confusing topic. If you try to apply configurations on structure transformation the chances are you can get lost. The best results can be achieved if a system used to manage engineering BOM is capable to model configurations, but very often it is not a case and companies are ending up with complex spreadsheets.

What is my conclusion? Some PLM pundits are saying “engineering BOM is a problem that was created by 3D CAD systems”. Because before that, engineering BOM was the first one to be created based on 2D drawings. In my view, 3D CAD added an additional information level that before was only captured in engineers’ minds. The old 2D process was a source for many mistakes and problems that were resolved by 3D CAD systems. However, to manage Engineering BOM is still a challenge in manufacturing organization, which can be resolved by careful alignment between design and engineering processes. Just my thoughts…

Best, Oleg

Want to learn more about PLM? Check out my new PLM Book website.

Disclaimer: I’m co-founder and CEO of OpenBOM developing a digital network platform that manages product data and connects manufacturers and their supply chain networks.


Share This Post