Printed Circuit Boards is a flat plastic or fiberglass board on which interconnected circuits or electronic components are laminated or etched. Manufacturing process of Printed Circuit Boards involves a series of photo imaging and etching processes. The manufacturing process involves Circuit Board processing and pcb assembly.
The manufacturing process starts with the schematic diagram of the circuit on the CAD software and then it is converted via computer aided manufacturing software to form the basic layout of the Printed Circuit Board itself. After the schematic design layout the process involves the formation of substrate. To create a PCB pattern or photo resist material are pressed onto copper foil. Panel is exposed to Ultraviolet light. After the removal of pattern mask the surface is sprayed with an alkaline developer which dissolves the irradiated photo resist and reveals the copper foil on the substrate. The panel is electroplated with copper. Tin lead plating is followed by electroplating of copper. Acid solution is then sprayed leaving the copper exposed on the circuit.
After the synthesis of the substrate the manufacturing process involves the next step of drilling and plating the holes. Several panels of substrate are stacked on top of each other and pinned together to place them in the machine for the drilling of the holes. After the holes are being made they are being deburred to remove excess material from the edges of holes. The inside surface of the holes are being made conductive from one side of the board while other side is electroplated with copper. The panels are passed through a re-flow oven which melts the tin lead coating of the substrate and is sealed with epoxy.
After drilling of holes the process is been succeeded by another step which involves the creation of the printed circuit pattern on the substrate. Printed circuit pattern is created either by additive process of subtractive process. In additive process copper is plated or added onto the surface of the substrate in a desired pattern leaving the rest of the surface unplated. Whereas in subtractive process the entire surface of the substrate is first plated and then the areas of the desired pattern are etched away.
The etched layers are been laminated together by pressing them with thin sheets of resin coated fiberglass under high pressure and high temperature. After drilling of the holes on the etched layers next step is to provide a coating of the solder mask to the panel in order to protect circuitry from soldering during assembling. Final step involves the pcb fabrication of each panel where each board is cut out of its panel and been tested before the shipment to the customer.