BOM 101: The four pillars of every BOM management solution

January 17, 2013

I suggest you an experiment. Invite two engineers and ask them to provide a definition for some of PDM/PLM related terms. I’d not be surprised if you will get more than two definitions. It is not unusual to spend lots of time during PLM software implementation meetings to define terms, language and meaning of things. Regardless on terminology, I found BOM to be a central element in every product development organization and business. It contains a recipe of your product, process and, at the end of the day, becomes a lifeblood of your product development processes. Thinking about BOM management solution, I can see four major things that need to be defined, discussed and clarified.

BOM and Part Lists

Bill of Materials (BOM) is a list of all items required to make a parent item. It includes components, raw materials and sub-assemblies. You may also include intermediate items identifying in-process elements to facilitate planning and other manufacturing processes. Depends on industry, people can call BOM differently. For example, in process industry, it can be called recipe or formula. Opposite to BOM, Part List is usually a term used to call a single level list for a specific level of assembly or sub-assembly.

Part Number

This is one of the most tricky defined terms in a whole product development and BOM management story. Here is a short definition. Part Number (PN) is an unique identifier that identify a single object in bill of material. However, the trick is how to define object and how to keep it consistent with your processes. Assigning part numbers is often complicated and one of the most discussed topics. The traditional definition of FFF (Form, Fit and Function) helps to identify the right objects. Interchangeable parts, substitiute items, special parts – this is only a short list of issues that comes into the discussion around part numbering process.

Routing

Think about navigation system with the road between different places. Now imagine part numbers. Routing is a roadmap that defines the path of part numbers across manufacturing floor by specifying workstations and labor time associated with every station. Usually routing applied to manufactured parts or items.

Drawings

Drawings represents a significant part of history and confusing engineering habits. Historically, drawing is the place where people put bill of materials for a product. It also solves the problem of Bill of Materials distribution in the company. At the same time, BOM on a drawing brings lots of disadvantages. In many situations, people don’t need drawing, but only need bill of materials and/or part list. Another point of confusion is numbering system. The discussion is about applying part numbers on drawings. In most of the situations, it represents the limitation of systems used for product development (PDM/PLM). To separate between Part Numbers and Document Numbers is the most reasonable ways to manage it, in my view.

What is my conclusion? Regardless of what systems you plan to use, I recommend you to have cross-department organizational discussion about these four pillars. Usually, it helps to understand product development processes. Engineering and manufacturing are two main organizations usually involved into BOM processes. To clarify terms will give you a tremendous value during PDM/PLM system implementation and integration with ERP. Just my thoughts…

Best, Oleg


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