In today’s world of electronics, you will find printed circuit boards in almost all electrical devices, be it computers or industrial equipment. Once the PCBs get fitted into these electronic devices, they start getting a lot of abuse. Over time, dust, moisture, and grime enter these devices and accumulate to a level that can lead to permanent damage to the device.
Therefore, a service industry responsible for cleaning and repairing PCBs is emerging in the market.
Cleaning a printed circuit board is a vital process in electronic device assembling. There are some reasons why you should clean a PCB:
Different types of contaminants can attack and accumulate in a PCB. They are of two types:
The accumulation of dirt and dust around PCB is widespread. You can use a small delicate brush like a horsehair paint brush to remove this dirt and dirt. This brush is soft and does not affect the components. However, this brush cannot reach all the areas of the PCB components.
To do a broader and deeper cleaning, you can use compressed air with care as it can damage vital components too. Some specially designed vacuum cleaners for PCB cleaning; however, they also cannot reach every area.
There are some components in PCB that come with a wax coating. In high-temperature operations, these components can act as a magnet for dust and dirt, leading to sticky grime, which you cannot remove with a brush or vacuum cleaner. Sometimes, the product also accumulates sticky soda, leading to a gooey mess. These contaminants can affect the PCB performance and thus should be removed as soon as possible.
You can remove such grime with a cleaning agent like isopropyl alcohol or IPA and Q-tip, clean cotton cloth, or a small brush. If you are using agents like IPA, you must do it in a well-ventilated area. Apart from IPA, there are several cleaning agents; however, each serves a different purpose. Always remember that complex cleaning agents can cause damage to component markings, plastics, capacitor jackets, or other delicate components like humidity sensors. If unsure of the cleaning agent, you can check that first on an old component or connector and see the effects.
Alternatively, you can use demineralized water. However, make sure to remove any moisture by adequately drying the board.
Cleaning PCBs with the hand is the most common method of cleaning. In this, you remove various contaminants and other solder substrates with the help of a brush or an alcohol solution. Apart from the brush, you can use different equipment also. This method is very simple and cost-effective as it does not require any special equipment and whatever you need is readily available around you. Another benefit of this method is that it does not cause any harm to humans and the environment.
However, as everything is done physically, the process may take time and not be enough to clean all types of dirt. Another drawback is that you cannot manually reach all the interior parts, and thus not an optimal method for cleaning dense PCBs.
In ultrasonic cleaning, you use a specially designed machine to clean PCBs. First, you must soak the board in ethyl alcohol solution so that dirt, contaminants, and any extra soldering material get loosened. After this, put the board in the ultrasonic cleaner’s cleaning bath. Now the equipment emits high-frequency sound waves into the bath solution, leading to billions of tiny bubbles exploding, which removes any contaminants on the circuit board. This process is known as cavitation.
As these tiny bubbles reach all the exposed surfaces, you can easily clean the dense and complex boards with ultrasonic cleaning. The strong and High-Frequency waves reach the board’s smallest and most difficult areas.
You can also call it vapor degreasing or vapor phase cleaning. In this method, you boil a chemical solvent that produces steam, which dissolves all the PCB dirt, dust, and contaminants. The gas phase cleaning method is very effective and environmentally friendly as you can use different chemical solvents for other contaminants. Further, you can filter the contaminants and use the chemical again after cleaning.
Like the ultrasonic cleaning method, this method is very effective as it can reach the deeper sections of the board where a physical brush cannot.
The deionized water wash method effectively and safely removes water soluble flux residue. In this method, you use a water-soluble flux in lead-free pastes or leaded pastes, and the solder gets cleaned by the deionized water. You can also use deionized water jets to wash and rinse the PCBs at high temperatures (144-degree Fahrenheit) and pressures (45 pounds per sq. inch). Following this, you can use air jets to dry the assemblies.
Soldering means fusing two metals using a metal with a low melting point at high temperatures. This metal binds the metal pieces like glue. You need flux in soldering as it helps in protecting joints from metal oxides which prevent effective soldering. The flux converts the metal oxides into salt and water, which then locks in flux after it hardens.
After soldering, solder flux can accumulate on the board as a tainted yellow crust. This is a common issue in printed circuit boards that you can fix quickly. For this, you need:
First, wet your brush with the alcohol and rub the board gently until you see solder flux disappearing. Once you see the board looks clean, dab it with a microfiber towel. After that, you can also use a flux cleaner which you will read in the next section.
For cleaning flux from the PCB, one of the most common methods is to use a cleaning agent like isopropyl alcohol. For this, dip cotton or a foam swab in the alcohol and rub it around the area. This method is enough when you need a visually flux-clean PCB. When applying the solvent, the flux residues do not evaporate. To remove them, you can dissolve the flux so that flux residues soak into the swab.
However, if you want to remove heavily active flux like RA and aqueous, you can rinse the board after swabbing. While the solvent is wet, rinse the board with an aerosol flux cleaner. Now hold the board in such a manner that solvent flows over the board and picks up any residues left and runs off the board.
It is common for a PCB to corrode due to water or any other source, and cleaning the PCB corrosion can repair it. Cleaning a PCB’s corrosion needs household items that any company can afford. However, it is essential to have fundamental knowledge before attempting the cleaning process. The process involves disassembling the board without damaging the components, and after cleaning, you need to reassemble them.
Here are some materials which you can use for cleaning PCB corrosion:
When your PCB is clean and clear, it helps you in future troubleshooting and inspection. If the circuit board does not have any contaminants and residual solder, you can easily detect the faults or any potential difficulties in the PCB.
Choose your PCB manufacturer wisely if you want to ensure a clean and high-quality PCB for your electronics. Some manufacturers follow IPC standards and rules for PCB manufacturing, ensuring that you are using the best PCBs optimized for your industrial equipment.
Need any help with PCB or PCBA manufacturing? Contact us now.
PadPCB is a professional PCB solution supplier in Shenzhen, China. We help our clients with everything from PCB design to the final mass production….