The first step in the manufacturing PCB (for two layer) is drilling. The CNC drill machines are enormous. Some of the machinces are setup to drill three panels at once and one of the bigger machines (pictured below) could drill six panels of PCBs simultaneously! A layer of aluminum foil sheet is laid down over the board stock to help absorb and distribute heat from the drilling process.
After drilling, the PCB panels have the aluminium foil sheet covering removed and are ran through a machine to remove burs and smooth out any other abraisions that may have happened during the drilling process. This ensures that surface is relatively uniform for the electroless chemical plating process, the next step. The aluminum foil sheet protects the board.
After being drilled, the boards are cleaned.
