From aiding precision in the manufacture of new products to shaving off production costs and keeping administrative processes lean, a BOM is critical at the preliminary stage of product development.
What Are BOMs and Why Do We Need Them?
A bill of materials is a document that details the raw materials, quantities, sub-components, sub-assemblies, and intermediate assemblies required to manufacture a product. Specifically, in electronic engineering, the BOM (also called an engineering bill of materials) contains the type number, characteristics, and functions of electronic components that are to be integrated on a PCB.
Project managers, design engineers, and supply chain professionals use BOMs to provide specifications for a product or component to the original equipment manufacturer (OEM), as they will of course be responsible for manufacturing it. OEMs rely on the data presented in the BOM to produce parts that suit a particular function.
The BOM is an essential document which helps manufacturers to allocate and manage resources efficiently, save time, and ensure the repeatability of production. Similarly, it helps clients to reduce costs and increase profitability by minimising wastage and administrative overhead.
What Information Should a BOM Contain?
An effective BOM should contain various fields that provide essential information about the part or product—see the below list (but note that it’s non-exhaustive and will vary between clients and manufacturers):
Every part listed in the document is a sub-part of the whole product. Therefore, each sub-component should be assigned a specific position in the hierarchy of the BOM. Many electronic BOMs utilise a multi-level, top-down or 'parent-child' structure for part designation, which shows how a specific part fits into the overall assembly.
The part name is a unique name assigned to a sub-assembly. It aids the identification process during assembly and is important for inventory purposes.
Every item in a BOM should be assigned a unique part number, as this helps the manufacturer to distinguish them from one another while also aiding the inventory process. Due to the large volume of components produced, electronic manufacturers utilise a part-numbering scheme to match components to individual clients, based on type, function, or product line.
A computer motherboard being outfitted with a hardware component. Image courtesy of Bigstock.
Each part listed in the BOM should have a detailed description that covers its function, characteristics, and how it relates to other components in an assembly.
Specifies the type of material that will be used to make the product. It is crucial for both clients and manufacturers to determine and agree on the most suitable material prior to production to ensure cost-effectiveness and product integrity.
The number of units per part should be specified in the BOM. It is used for assembly purposes by the manufacturer, and also to guide the purchasing decisions of the client.
The client must obtain the cost per unit of each item listed in the BOM for pricing and administrative purposes.
Includes remarks, comments, or suggestions to inform and guide relevant parties involved throughout the product lifecycle.
How Can BOMs Be Improved for Project Needs?
Some challenges in engineering BOM include inaccessibility of information, inadequate or untimely change management, human error when it comes to specifications, and complicated product sorting. Below are some of the ways that these problems can be resolved:
Make Information Accessible
Since BOM are typically used by professionals from various disciplines, it is essential to present the information contained in a format that is usable by all parties involved in the production process. For an engineering BOM, this involves translating technical specifications to a purchasing/production-ready format. Pictorial information (consider diagrams and CAD drawings, for instance) must be communicated effectively.
FORTE: the intelligent bill of materials management tool (offered to Mouser subscribers for free). Image courtesy of Mouser Electronics.
Prepare for Changes
On occasion, it may be necessary to revise or modify some information in the BOM (for example, when a material is out of stock or the client has decided to proceed with a new prototype). Change management at every phase of the product lifecycle must be carried out by the appropriate personnel, captured in a timely fashion, and communicated to all parties concerned.
Automate BOM Management Using Software Tools
The world has become increasingly automated, and the manufacturing sector is no exception, of course. These days, it's common to have BOM in a software format for product lifecycle management (PLM). Automation helps save time, aid traceability of parts, and improve accuracy in BOM management by eliminating the human error factor.
Use Intuitive BOM Tools for Product Sorting
To minimise the time spent on identifying and/or sorting parts, BOM software tools must become more intuitive. A good example of a company that implements intuitive BOM software is Mouser Electronics: one of the world’s largest semiconductor and electronic component distributors, which uses its FORTE Intelligent BOM tool (see above image) to simplify product sorting. FORTE helps engineers and buyers quickly find components and suggests alternatives with similar functions within the same price range.
Creating an effective BOM can seem like a daunting task, as a lot of thought goes into creating a document that fully satisfies product requirements while keeping production costs low. The solution is to automate the process using intuitive software tools: effective BOM management will keep design engineers, project managers, supply chain professionals and more—all ahead of the curve.