PCB News - What is the purpose of PCB need bill of materials?

All components are under one roof

During the PCB assembly process, the BOM can provide information about the components under a single roof, such as their quantity, reference code, packaging, etc. By preparing a bill of materials that includes all updates, designers will save a lot of time and effort during the PCB design process. Parts List. If the BOM is updated correctly, there will be no chance for redesign in the later stages. Therefore, the updated BOM can save time and effort.

Cost estimate

As mentioned earlier, the bill of materials is a file that contains all the components needed to assemble the circuit board. For PCB projects, cost estimation is a major decision. The BOM list can be very useful when designers are in the initial stages of determining how many boards they need and the parts required for those boards.

Now, most of the time it is difficult for designers to meet the target cost of the entire project. By analyzing their BOM, they can calculate the availability and cost of different components. Therefore, they can change the design as needed in the initial stage to fit the target cost range.

Nowadays, most PCB manufacturers provide BOM tools to conduct cost estimation checks with different suppliers. These tools compare the parts mentioned in the list with the real-time inventory provided by their designated suppliers. The BOM tool also lets the designer know if a part is available for purchase. If not, an alternative part number with the same specification will be suggested. Discounted prices are taken into account when ordering components in bulk. Therefore, these tools are very helpful for cost estimation.

How to create a bill of materials?

Simply use a spreadsheet and enter the required parts list to create a BOM. This is a tedious process that requires a lot of time and energy. But with the advancement of technology, there are now ways to create a BOM that is updated based on the availability of parts. This is why designers now choose software tools to create bills of materials. In the design phase, the BOM is generated from the schematic ECAD tool.

Using these ECAD tools, designers can first draw PCB schematics. These tools will contain information about the part numbers in the library. When the designer adds each part to the schematic, the part information is also extracted from the library. The ECAD tool uses the same information to create a bill of materials for that particular schematic.

Among the available software, the most commonly used are Altium Designer, Allegro PCB Editor, KiCad, etc. Please also read how to export Gerber and production files in Altium Designer.

After BOM files are created, they can help designers in the following ways:

Total cost: Using BOM, PCB designers can understand the total cost of the number of circuit boards to be assembled.

Availability of parts: The selected parts should be in stock. After generating the bill of materials, you can check the inventory of the required components.

Life cycle: The parts to be ordered should have an active life cycle.

Bulk order price: When ordering in bulk, some suppliers will offer discounted prices. Since the BOM has all the required parts, bulk orders can be placed.

Easily change the format: You can easily change the format of the generated BOM. This provides the option to send the BOM in any format required by the manufacturer.

The importance of having a BOM that includes all the necessary components and their specifications is now very clear. Therefore, the designer should first look at the template provided by the PCB manufacturer. After that, they can generate a bill of materials in a specified format, and use the BOM tool to check it and get a quote. To verify your bill of materials, you can view our BOM checker tool mentioned in the previous section of this article.