The Manufacturing Process of Circuit Boards

Prototype circuit boards

Generally speaking, there are two different techniques that can be used to putting together a circuit board. One is called Surface Mount Assembly and the other is known as the Through Hole Construction. Two other types of circuit assemblies that are usually used are called the integrated circuit and the hybrid circuit. Let’s take a quick look at these four methods to give you a better idea of prototype PCB fabrication.

The Surface Mount Assembly method is made by mounting the elements directly on to the circuit board. This is a more common technique than the ‘through hole construction’ method. However, both types of technology can actually be used on the same board at the same time.

The circuit board for the surface mount assembly technique is flat and more often than not, made of tin lead, silver or gold plated copper pads. These pas are called solder pads. The solder pads are saturated with solder paste. Solder paste is a mix of flux and solder particles. After this part of the prototype PCB fabrication is complete, the boards then move on to a conveyor belt to be put in to a soldering oven. They are pre heated and then put in a high temperature area in order to melt the solder particles fully. The reason for this is to bond the leads to the solder pads.

Sometimes in prototype PCB fabrication, the circuit boards have two sides. If this is the case, when one side has finished the above process, then it is given time to dry and set in place. Then, the whole process is repeated for the opposite side of the board.
After both sides are done, the boards are carefully look at to see if any of the components have become misaligned or to check if any parts are missing. If something is wrong and a repair is needed, the board has to be sent to a station to get it fixed. Once in proper condition, the boards are then sent off to a testing area to make sure they also function as they should.

The Through Hole Construction technology is typically completed by the use of lead on the elements of the board. Holes are drilled into the circuit and the solder pads are placed much like the other method.

This technique is used to very strong mechanical bonds. However, even though the boards themselves are strong, the whole process is a lot more expensive. The holes cause the area where routing can happen to be limited as well.

When it comes to the prototype PCB fabrication process, most engineers prefer the hole construction method because it is more compatible with breadboard sockets which are often used.

The Integrated Circuit or IC is generally made using a semiconductor. This kind of circuit is used for devices like microprocessor and cars. An IC is recognized because of how many transistors it contains. If a smaller board is being manufactured and had no need of large packages then this method is beneficial.

The Hybrid Circuit method is closely related to the integrated circuit method. The difference here is that it is a miniature circuit that is made up of all different individual devices. The devices are typically bonded to a circuit board.

Another difference between the hybrid and integrated circuits is that hybrids have certain elements that are not included in the process of making the circuit board.

Thick Film Technology is the last one we are going to talk about here. This method is usually used together with the hybrid and integrated circuits. Screens are printed onto thick films and that is what is used in order to connect the two different technologies. When this method is used, the designer has to choose the resistor value himself, which actually makes the process a lot easier on him. The technology itself has been around the for a long time. The first appearance was in the 60′s when Ultra Electronics used to make circuits with a silica glass mixture. The hybrid and integrated circuit board methods eventually replaced this all together.

Hopefully, after reading this article, you now have a little better understanding of the fabricating process as well as prototype circuit boards after they are actually made.

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