What Information Is Required for PCB Assembly and Manufacturing?

Recently, we have received many PCB assembly requests from customers, but a common situation often arises—some customers only provide a photo of an existing circuit board and ask us to reproduce it directly. In reality, without complete design documentation, it is impossible for us to proceed with PCB manufacturing or assembly. Most customers understand this once it’s explained, but a few may question our professionalism. To help everyone better understand the reason, let’s take a look at what information is required for PCB assembly and manufacturing.

First of all, when customizing a PCB, it is essential to provide a complete set of Gerber files. Gerber files are the “blueprint” of the circuit board. They contain detailed graphic data for each layer—such as copper traces, solder mask, silkscreen, and drill layers—which guide the fabrication and layer alignment process. Without Gerber files, PCB production simply cannot begin.

Next, during the PCB assembly stage, the most important document is the BOM (Bill of Materials). The BOM lists all electronic components with details such as part numbers, packages, quantities, and reference designators. It serves as the foundation for component sourcing, placement, and soldering. The accuracy of the BOM directly affects material matching and production efficiency. In addition, a Pick & Place file is also required. This file contains precise placement coordinates, rotation angles, and orientations for each component, allowing the placement machines to accurately position components on the PCB. Finally, if the product requires functional testing, test instructions or test programs should be provided to verify the product’s performance after assembly.

In summary, the key documents required for PCB assembly and manufacturing include: Gerber files, BOM, Pick & Place files, and test documentation. If a customer does not yet have these files, it is necessary to first go through a product development stage, where engineers design the PCB according to the functional requirements. Once development is complete and the design data is generated, production and assembly can then proceed based on those finalized files.