The Importance Of (BOM) Bill Of Materials in PCB Assembly!

A bill of materials (BOM) in PCBA manufacturing is a list of raw materials, components, and parts required to manufacture a complete circuit board. It mainly includes component name, brand, part number, required quantity, etc. It may also contain the manufacturer or supplier name, additional features column, and comments section.

Creating an accurate BOM is important, especially when you hand over PCB assembly to an OEM electronic manufacturing services company. The electronic manufacturing service company will generate a bill of materials based on the BOM list provided by the customer, and verify and approve it. Generally speaking, the BOM table is mainly used for component procurement in the PCB model cloning process. The BOM facilitates proper planning and smooth operation. If a BOM part is missing during validation, this can lead to increased costs and delays in the need to locate the missing part or an alternate source, or the receiver board is full of errors that may not be corrected.

BOMs are generally divided into several categories. Classification makes it easy for suppliers to find their customers in the BOM.

1. All core PCB elements must be listed in the BOM list, and each element in the PCB, especially components and wiring, has a unique identifier. The BOM contains descriptions or comments for each component as part of the unique identification. This way, the BOM will allow you to easily cross-reference information between the BOM spreadsheet and the PCB layout.

2. Each component has a unique ID or code, MPN is the unique identification number provided by the component distributor. This information alone is what you or your manufacturer will need when ordering PCB parts, so it's important to make sure these numbers are accurate and up-to-date. And there is a lot of additional but useful information in the BOM list, such as product-related notes, structural details, properties, tolerances, and more.

3. The number of boards required is also listed in the BOM list. Record the number of parts to be used in each PCB assembly or subassembly to help guide purchasing and manufacturing decisions and activities.

4. It is best to mention the design specification or part number description of each part.

5. It is better to mention the size of the part number, because it can give you an idea of how much physical space it occupies on the circuit board, reducing the waste of time and cost in PCB assembly.

6. It is a good practice to provide the manufacturer's name and an optional or alternate name, you give the BOM to the buyer, and if the part is out of stock, they may use this information to find a replacement part.

Creating a bill of materials is not only a necessary step in the PCB development process; it also plays a decisive role in PCB assembly, which is what makes your product design a reality. As a professional electronic manufacturing service company, TECOO provides design, manufacturing, supply chain and product management services.