What Is a Bill of Materials (BOM)

The bill of materials software is something that often considered a simple thing. After all, what can be complex in a list of parts? However, as we can see in practice, manufacturing companies are usually underestimating the complexity and fail to manage it properly. BOM engineering is a complex discipline requires sophisticated data management and you’re trying to avoid it, the results can be brutal and painful. The results are usually very painful and coming faster than you can think – missed components, wrong cost estimation, delayed product deliveries, and frustrated engineers and customers running around trying to figure out where is the last and most updated bills of materials.

At OpenBOM, we believe in openness and simplicity as the main drivers to help companies to get up to the speed with data management science behind Bill of Materials. It should be easy to start using OpenBOM and discover how to do it step by step.

The Bill of Material is a structure representing all items needed to make a product. Depending on the product and business it includes a different level of details about how the product is engineered, manufactured, assembled, sold and maintained. Every engineering and manufacturing business should be concerned if parts and assemblies, as well as any other related data, are not managed properly.

What should be the content of the Bill of Materials?

Very often companies are asking – what to include in the BIll of Materials? A very simple answer to this question is EVERYTHING. The idea of not having something in a BOM is bad and to hope that you will remember what is needed is a recipe for disaster. Very often, we’ve been asked about what is a typical data set of the Bill of Materials. Here is a quick summary of what I think is absolutely essential.

Key Items and Elements of Bill of Materials 

Part Number: This is a unique string that identifies every single component in the product. Not all part numbers are the same. You probably heard about OEM, Manufacturing, Suppliers and many other part numbers. Those are additional pieces of information. You might not use all of them. But, to have a unique Part Number for every single item is a must to have to keep things organized.

Description: It usually gives the organization a simple way to look at the details about parts and components. Used for search, simple identification Description is not unique and must not be used to reference parts for any purposes except human interaction. Part Number is used for everything else.

Part Name: Names make it easier for organizations to track components. Many systems have internal names with specificity useful to Operations, Test, and Engineering teams. A separate nomenclature might be with customers in Sales organizations. Unlike part numbers, part names aren’t necessarily unique. Consistent use of part names like connector, adapter, and cable, can help keep everyone on the same page.

Unit of Measure: A very important piece of information that helps to identify how to measure the quantity of the part.

Type (s): Usually absorbs the different types of information to classify part of help to identify how to manage the part. Organizations can apply multiple types to classify parts and how data about part can be processed.

Revision and Phase: This is used to identify the level of maturity and specific changes. Companies are using various practices when creating new part numbers of revise existing parts.

In addition to these parameters, organizations are usually including information about the manufacturer, suppliers, cost, and other pieces of data in BOMs.

Part vs Usage of the Part.

The information I mentioned above is usually the same about the item (part, purchased assembly). However, another group of information is typically included in BOMs and it represents a specific part usage.

• Quantity: it is the ultimate way to say how many pieces of the part you need in this product. Note, in some cases (for instance BOM), quantity can be only calculated.
• Reference Designator: Typically used in the electronic Bill of Materials usually represents a uniquely identified instance of the part (assembly).
• Location: It is typically used in mechanical BOMs to differentiate between instances of the part/ assembly.

Effectivity

A very important element of the Bill of Materials. Effectivity is usually representing specific characteristics saying if a part (or assembly) can be used and under what conditions. There are different types of effectivity – date, configuration, serial number.

Configurations, Configured vs Resolved BOM

Last, but not least piece of information is related to complex products having multiple configurations. A BOM that contains information about multiple configurations usually called “configured BOM” and the BOM that represents information about a single configuration is called resolved.

SIngle-level, Multi-level, Flattened.

A list of components represented as one level is usually the basic way to plan the BOM. However, components are connected into assemblies and those usually have sub-assemblies. This is a simple single-multi-level structure. A flattened BOM is a report that summarizes the usage across multiple levels.

What does a BOM look like? 

OpenBOM Bill of Materials core elements are represented using the Reference-Instance model and described by the following picture. You can see references (items) and their instances combined into parent-child relationships.

OpenBOM provides a super-efficient and easy-to-use user interface to view, control, and collaborates around the Bill of Materials.