Different Steps Involved In PCB Assembly

What is PCB Assembly or Printed Circuit Board Assembly? It is the process of putting together electronic components to a printed circuit board or PCB by soldering. Click this website for more details. The finished product (the board) is called Printed Circuit Assembly (PCA) or Printed Circuit Board Assembly (PCBA).

We can find PCBAs in gadgets, appliances and other electronic products. We also have to put into mind that Printed Circuit Board Assembly (PCBA) is different from circuit board manufacturing. PCBAs are essential for every electronic product or item so as to make them functional. In other words, it is the essence or the most important part of an electronic item.

There are various steps in PCB Assembly:

1. Preparing Circuit Board Surface

2. Placing the Parts or the Electronic Components

3. Soldering

4. Conformal Coating

5. Cleaning and Inspection

6. Testing

But before we start making our circuit board assembly, there are certain things that we should prepare first.

We will need:

1. Circuit board

2. Electronic components

3. Soldering materials such as solder wire, solder bar, soldering paste, solder performs (It depends on the kind of soldering to be done.)

Once we have the PCB and the parts that we are going to use, we can start the PCB Assembly by placing the electronic components on the circuit board and proceed to the process of soldering.

Now, there are two soldering techniques in PCB Assembly: the automated technique in which pick-and-place machines are used; and the manual technique in which expert technicians solder manually minute electronic components under a microscope. They also use tweezers and a soldering iron with fine tips in performing a manual technique.

PCB AssemblyThere are ways in which components can be attached in PCBs. One is the Through-Hole Soldering Construction or Process in which the electrical parts have leads or legs that are inserted into the holes of the circuit board. Later on, they are soldered to the board either manually (hand soldering) or by wave soldering. Also, both processes can be used in Through-Hole Construction.

Another one is Surface Mount Technology (SMT). In this PCB Assembly process, the electronic components don’t have leads or legs. These components are mounted on the surface of the printed circuit board. Surface Mount Technology (SMT) also uses equipment, soldering materials and electronic parts that are different from the Through-Hole Soldering Process. Surface mount components use automated machines to be able to put together or assemble the parts into their circuit boards.

Usually, SMT process is used for mass production of circuit boards as they use pick-and-place machines to do the job. Automated machines are not practical for production of small numbers of printed circuit boards.

Once the electronic parts are soldered to the circuit board, it should undergo conformal coating. This is done by applying the coating by spraying or dipping the PCB after the soldering process. This is done to avoid corrosion and leaking of current or possible short circuits in the circuit board due to condensation.

What comes next is cleaning and inspection. The PCB is washed with de-ionized water to remove flux residue. Flux residue is the combination of cleaning agents, heat and agitation. Flux residue should be removed because when it is not removed from the circuit board, after a period of months, it becomes sticky. It also becomes slightly acidic and will lead to the weakening of solder joints, thus, causing damage to the circuit board.

After washing, the PCB is dried via air compressor to remove any remaining water.

The PCB is tested so as to check and find out if it is fully functional. If problems occur, e.g. it is dysfunctional, it is returned to the technician to find out where the problem lies. So, the process of soldering, washing, inspection and testing take place again.

Finally, when the PCB assembly is fully functional, they are wrapped in anti-static bags for storage or transportation purposes.

PCBAs are static sensitive. So, improper handling can lead to static charge transmission in the circuit board, thus, resulting to components damage.