All You Need To Know About PCB Manufacturing And Assembly

  • Ever wondered what your laptop or computer have in common that allows them to function?

    Your first guess may be a motherboard, but to be more precise a motherboard is actually a PCB – Printed Circuit Board. This is a board that is made of fiberglass coated with a thin layer of copper on one or both of its sides. PCB holds together and electrically connects together all the electrical components such as transistors and capacitors using conductive pathways. Apart from laptops and computers, PCBs are also used in many electronics such as phones or television remotes.

    PCB manufacturing is carried out in two main phases called PCB fabrication and PCB assembly which further follow many steps. Before any product can be manufactured, a blueprint is needed. The case of PCBs is no different. To begin with, CAM software generates and verifies the fabrication data. Next, copper patterning is done by producing a replica of that pattern onto the laminate on the copper of the PCB which is covered by resist which hardens on exposure to UV light unveiling the copper pathways. This is then preceded by inner layer etching, in which ferric chloride is used to incise the pattern onto the copper by removing any unwanted copper.

    The next stage, lamination, is quite challenging as it requires high levels of precision. This stage is used in the manufacturing of multi-layer printed boards where multiple boards are laminated by the application of pressure and heat. Once this is done, to join several layers together, holes are drilled at specific points through the PCB followed by electroplating using copper in order to ensure that the connections have conductive outer layers.

    Having done the electroplating, the outer layer etching is done to remove any unwanted copper and the exposed parts of copper are covered with solder or any anti-corrosive metal.  The parts that do not need to be soldered are covered with a solder mask such as liquid photoimageable mask. Following this, PCB silkscreen is produced using software which aids in printing text on the board. Lastly, the bare board manufactured is tested for any faults and the board moves to the PCB assembly.

    Following fabrication, the second phase of manufacturing is PCB assembly in which the electrical components are packed on the bare board. The two methods of this being the Thru-Hole and Surface Mounting. Firstly, a solder paste is applied on designated areas where the electrical components are to be placed. The components are then placed on these areas carefully using machinery and the plate is heated followed by solidification to secure the components in place.

    Initially, the Thru-Hole Mounting method was used in which the component leads are put into drilled holes on the PCB surface but further research led to the development of Surface Mounting in which the components are placed directly on the PCB surface.

    There is immense importance of these processes to produce PBCs to cope up with the increasing demands of today’s electronic market that emphasizes on the manufacture of more efficient electronics. This advancement of technology would hence require more manufactures in the future thus serves as a great career opportunity.