What is a BOM (Bill of Materials) and What is it Used For?

In this blog, we explain what a bill of materials is, what they are used for, the different variations of BOMs, and why they are useful records to have.

What is a bill of materials (BOM)?

A bill of materials (BOM), also known as a product structure, is a list of all the items needed to construct, manufacture, or repair a product or service. A BOM functions as a centralised source that contains all the information needed to manufacture a product from the raw materials stage.

The BOM contains an extensive list of raw materials, sub-assemblies, intermediate assemblies, components, and parts involved in the creation of a product or service, as well as the quantities of each, their cost, and instructions on how to assemble them.

A bill of materials usually appears in a hierarchical format, listing the finished product at the top of the list, working down to the individual components and raw materials.

There are types of BOM specific to the engineering used in the design process and those that are specific to the manufacturing used in the assembly process.

Why is a bill of materials necessary?

A bill of materials is a vital item to have because of the depth of information contained within it. A BOM is necessary not just to build a product, but also to order replacement parts and identify problems when repairs are required. 

A BOM allows manufacturers to plan the purchase of raw materials, estimate the costs of production, maintain accurate records, as well as reduce waste and the chance of errors during the entire process.

BOM structures

Depending on requirements, a BOM can be a fairly simple, single-level document that contains just the finished product and its subassemblies, but these are often unsuitable for complex projects, troubleshooting potential problems or replacing parts. This is why multilevel BOMs are required, where each sub-component has its own child components, right down to the raw materials.

Types of BOMs

Three different types of BOMs may be used, depending on the needs of the business. These are Engineering Bills of Materials (EBOMs), Manufacturing Bills of Materials (MBOMs) and Sales Bills of Materials (SBOMs).

EBOMs define products in the way they are designed, showing the structure from a functional perspective, and usually include mechanical or technical drawings. They include alternative and substitute part numbers and each line of the BOM includes the product code, part name and number, description, quantity, measurements, and specifications or features of the product.

MBOMs define products in the way they are built, showing all the assemblies and parts required to build the finished product ready for shipping. This means the bill also includes the materials required for packaging and information on any processing required for parts prior to assembly.

SBOMs define products in the sales stage. These bills of materials list finished products and the components required to develop them separately in the sales order document.

A bill of materials is an incredibly useful record to have, not just for physically developing and maintaining a product, but also for the effective planning of the entire process, such as cost predictions and waste reduction. 

Here at Rebound Electronics, we offer Data Driven BOM Analytics to help you manage your data effectively.