From Gerber File to Physical PCB: What Happens Inside a Circuit Board Factory

Exporting Gerber files and receiving finished PCBs involves a multi-step subtractive manufacturing process that most designers rarely consider. Each copper layer begins as a full sheet, with unwanted material chemically etched away rather than deposited, before inner layers are laminated together under heat using prepreg bonding material. Vias are then drilled and copper-plated to create electrical connections between layers, followed by outer layer etching, solder mask application, silkscreen printing, and surface finishing. Every board undergoes electrical testing for opens and shorts before shipment, a process that collectively explains why fabrication takes days rather than minutes. Understanding this pipeline is practically useful for designers, as default DRC rules in CAD tools are generic and may not match a specific fab's capabilities, potentially causing manufacturability issues on tight designs.