PCB Fabrication Overview and Methods
A PCB (printed circuit board) is the basis of almost all contemporary electronic circuits ever created. It revolutionized the way electronic parts and components are linked together. Prior to its introduction in the early 1900s, traditional designs are generally made of separate electronic pieces that are connected individually by several wires to one another. This technique was used for a while before the demand for smaller, more compact electronic circuits rose as the requirement for more portable devices have grown.
It was in 1925 when the first patent of the PCB was submitted by Charles Ducats, which included a way of “printing” electrically conductive inks on a piece of insulated substrate to be used as an electrical medium. This started the name “printed circuits,” and PCB fabrication also began, which was considered as ground-breaking at that time as it made the creation of smaller electronic circuits possible.
Today, PCBs continue to satisfy the growing demand of the public when it comes to up to date technology. Modern PCB designs have no less than three specific functions which are: to give electronic parts a mechanical base, to electrically link the said parts together composing a whole circuit, and to supply connections for the input and output of a given circuit. There are many more but these three are the essentials.
There are also three main forms of PCBs based on structure and they are single-sided, double-sided, and multi-layered.
Their names refer to the way circuit designs are printed into the insulated surface during PCB fabrication. Single-sided PCBs have printed circuits on only one side of the board, while double-sided types have them on both sides. A double-sided PCB is able to carry more components, thus is appropriate for more complicated circuits. Multi-layered boards, meanwhile, are made up layers of printed circuits and insulations sandwiched on top of one another. It is able to accommodate even more components than a double-sided one and is the most commonly used type in modern devices today.
There are two methods of fixing electronic parts on a substrate and they are through-hole technology (THT) and surface-mount technology (SMT). THT was the original method used in attaching parts in PCB fabrication. Components such as resistors, capacitors, insulators, and diodes are made with legs that can be inserted in holes and then soldered to pads at the opposite side of the panel.
Since the 1980s the THT methods was replaced by a more cost-effective technique and that is the SMT. In the SMT method, electronic components are not inserted through holes but are directly soldered on the surface of the substrate. To hold the parts in place, a type of solder paste is applied to the points of contact on a circuit board and then passed through an oven for the paste to melt and establish fixed connection.
Even though the SMT method entails more precise attention in setting up the parts, it eliminates the lengthy process of drilling holes that is normal with the THT method. It also takes away the necessity of the pads on the other side of the substrate where the parts are soldered. These pads can actually take up so much space that could have been used for the design of much complex circuits.
There are no standard circuit boards when it comes to PBC fabrication. All designs come from individual designers and each circuit is usually unique from one another. PCB designers use computer-aided design software or CAD in creating the blueprint of a circuit. Once they finish the design in the computer, it can be printed out and then sent to the manufacturers to be mass produced. This makes the PCB fabrication process complex by nature.
Pcb fabrication is all about the assembly of circuit boards used in electronics and computers. The layers of PCBs are assembled along with their specific surface patterns in order for them to be used in manufacturing electronics.