What is a bill of materials (BOM)?

A bill of materials (BOM) is a list of raw materials, components, and parts required to manufacture a specific end product. It mainly includes part number, name and quantity. It may also have the name of the manufacturer or supplier, other function columns, and a comment section. This is the key link between the customer and the manufacturer, and it provides detailed information about the procurement item. If you want to produce products within your organization, you can also provide them to internal departments.

Why is BOM important for PCB Assembly?

Designing a PCB and then assembling many PCBs is very complicated. Therefore, it is very important that you fill in the information accurately. Here are some reasons for the importance of BOM:

The list is very convenient, so you know exactly what materials you have, the quantity, and the remaining parts you need.

It also estimates the number of employees required for a particular assembly based on the purchased parts.

BOM helps correct planning and smooth operation.

BOM is required for review, it helps to track the parts purchased and the parts available in the inventory.

Accurately obtaining the parts you want or parts made by a specific manufacturer is essential.

If it is not available, you can discuss and provide other options immediately.

Factors to consider when making BOM

If you receive an order for 50 PCB components from a consumer electronics manufacturer, you need to consider the following points when making a BOM:

It is not a good idea to consider the full quantity you think you need (50 PCB components at a time).

Instead, consider a PCB component, find out the type of PCB and the required components, and only list the detailed information of the parts of a component.

Let your team of engineers figure out all the parts needed.

Send the list to your customers for verification.

Almost always, you may need multiple BOMs.

After final discussions with your team and customers, determine the BOM.

BOM must answer the “when”, “what” and “how” questions related to the project is essential.

Therefore, never make a BOM hastily, because it is easy to miss some parts or mention the wrong quantity. This will result in a large number of back and forth mails and wasted production time. Most companies provide the BOM format, and it is easy to fill out. However, in addition to the BOM, it is essential that your PCB components must be accurate and function well. Therefore, it is very important to deal with reliable PCB component manufacturers and service providers.