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Complete guide to PCB Cleaning in PCBA process


It is inevitable that impurities, dust, rosin and solder will be produced on the surface of the printed circuit board (PCB) during the production process. It must be cleaned when installing and moving the PCB. Otherwise, the quality of the product will be seriously affected. This article introduced all the aspects of PCB cleaning, hoping to be helpful to you.

What is PCB Cleaning?

What-is-PCB-CleaningSince circuit boards are a common component of electrical devices like computers, laptops, and smartphones, they do become filthy over time and allow dust and other particles to enter the circuit. Therefore, constant cleaning is necessary for the PCBs to start functioning properly. If appropriate cleaning is not done promptly, issues like overheating and component failure may develop.

Why PCB cleaning is required?

PCB cleaning is done to ensure proper working of the circuit board and to get rid of problems like overheating and poor performances. Its main purpose is to get rid of dust particles, debris and flux residues. After the cleaning process, the PCBs are clean and are easy to inspect.

What is used to clean PCB?

The flux residues and dust particles are mainly removed by Isopropyl Alcohol in the circuit board assembly. The reason behind using the C3H8O is because it is cheap, easily available and quick evaporation. Isopropyl Alcohol is also non toxic and contains fewer mixture of chemicals. We can also use Sodium Bicarbonate or baking soda for cleaning of the circuit board and to remove grime without damaging the board.

What contamination can be removed through PCB cleaning?

What-contamination-can-be-removed-through-PCB-cleaningThere are four types of contaminants which are present and can be removed through PCB cleaning. These are following:

● Organic contaminants
Organic contaminants include rosin solder and also fluxes which have activation grades like the original Rosin, Activated and mildly activated. Non polar oils and greases are also included organic contaminants. Organic contaminants can be removed by special fluids and flux removals.

● Inorganic Contaminants
Flux and solder paste are the main inorganic pollutants which include the halogens, bases and acids. They mostly come from polar residue left by led free fluxes. Inorganic contaminants require aggressive cleaning fluids mainly the white stubborn white residue.

● Water
Water pollution is a form of inorganic contamination and could provide specific PCBA removal difficulties. The contamination of water is removed by vapor degreaser which uses batch drawing. The quantity of water tells us which method should be adopted of drawing fluid methods.

● Particulate
These polar contaminations are insoluble and they cannot be dissolved in water or the cleaning fluid. Different particulates are present, some large ones can even be seen through the naked eyes while the smaller ones cannot. These contaminants can be removed by adding agitation to the cleaning fluid.

How do you clean PCB before soldering?

In the older boards there would be contaminations as well as oxidation that could be collected over time so cleaning of the circuit board must be performed before soldering. In the first step the acetone solution is used to soak the circuit board, after which a simple brush or a banisher is used to get rid of the contaminants at the solder connection. Deionized water is used to clean the board for 3 minutes after which the board is taken out. At the last step, to dehydrate, 100% ethyl alcohol is used.

How do you dry a PCB after cleaning it?

A lint free wipe is used to dry the PCB after cleaning. That will clean up all the excess drops of the spray that are spread on the circuit board. When pushing the wipe underneath on low surface mounted components, the wipe will dry out the spray.Besides, you can dry through PCB baking.

What is PCB cleaning machine?

This machine is used to electronically clean the PCB and all the circuits of the board. Dust particles, excess spray or water drops as well as debris can also be cleaned by using a PCB cleaning machine. Any kind of useless material is also removed by PCB cleaning machine.

What is PCB ultrasonic cleaning?

What-is-PCB-ultrasonic-cleaningThis machine uses sound waves of very high frequency for the cleaning of PCB. The emitted sound waves explode the billions of tiny little bubbles in the cleaning solution of the liquid path which removes all the possible contaminants which were present in the circuit board. This process is known as cavitation.

How do you remove corrosion from a PCB?

If you want to remove corrosion from a PCB, cleaning it with either baking soda or distilled water would be helpful. For making its thick paste one part of baking soda is mixed with two to four parts of water. After that just scrub the already made solution to the areas where corrosion is present and allow the board to dry for around 20 to 30 minutes.

Is PCB dust harmful?

It is harmful and shouldn’t breathed in as it can cause respiratory problems. Also, the PCB used as resin in fiberglass is toxic for health and can be harmful. The asbestos dust can cause you cancer and other diseases. A progressive lung condition known as asbestosis is also brought on by asbestos.

What is the white stuff on PCB?

The activators in the flux or the salts are the white stuff which is present on the PCB. Keep in mind Its not always the case as described. When different chemicals or even heat is mixed with salt the white residues may form. Which will result in the corrosion of the delicate circuit.

How do you clean dried flux?

The easiest way to clean the dried-out PCB flux is to, first soak the cotton with Isopropyl Alcohol, or any other kind of cleaning solvent and just apply it over the repaired or infected area.

FAQ about PCB cleaning?


Can rubbing alcohol damage PCB?

A rubbing alcohol also known as 70% isopropyl alcohol should be used for cleaning and rubbing the PCB. A cleaning solution should not be sprayed directly on your computer’s surface. After lightly wiping the area with the towel, spray your cleanser over it.

Can we use petrol for PCB cleaning?

Yes, you can use petrol for the cleaning of circuit board. On PCBs, both petrol and isopropyl alcohol work well.

Can dust damage PCB?

It may cause damage to the PCB under certain conditions. Furthermore, dust acts as an insulator, which can lead to additional overheating as well as clog up integrated circuit boards which will cause short circuit.

Can you vacuum a PCB?

Using a vacuum for the cleaning of PCB should be avoided as the PCB surface might get staticky if you blow air through a vacuum. A gentle air source should be used to clean out the particles and dust from a PCB.



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