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Surface mount cleaning of PCB and PCBA

When we deal with electronic parts and soldering, we often encounter a common rule of thumb. The common saying is to always ensure cleaning surface mount PCB after soldering. Cleaning the surface of the PCB not only provides better functionality and reliability, but it also looks cleaner and more pleasing. When we deal with PCBA and SMD components, we often use solder iron and flux to accomplish the work. This task leaves traces on the PCB board that could heavily impact the PCB and PCBA functionality.

In this article, we will cover why it’s essential to clean the surface of your PCB and PCBA. When to clean it, how to clean it, and the benefits of maintaining a clean PCBA surface.

Surface mount cleaning using PCB cleaning chemicals

We all know printed circuit boards and SMD components are sensitive to touch, especially liquids. According to this, how do you clean the surface of a PCB or PCBA? There are multiple ways to accomplish that. The most popular cleaning agent is IPA, which is isopropyl alcohol.

The alcohol can efficiently clean the surface without damaging the sensitive components. For efficient cleaning, we suggest using an anti-static brush and softly brushing the flux/leftover paste from the PCB.

Isopropyl PCB cleaning agent is highly toxic, and avoiding breathing the IPA fumes is recommended. When cleaning the surface mount of the PCB, ensure to wear a mask and proper protection. Except for Isopropyl, a common way is to use Acetone which is commonly available in pharmacies. Large pcb factory submerge the PCBs in a solution to clean them from any possible contaminants.

Demineralized water is another alternative for PCB surface cleaning, although less prevalent. The technique has a similar effect, but Isopropyl is slightly cheaper and easier to find.

Improvements in PCB surface cleaning

But why? Why do we need to clean the PCB surface mount after welding the components? The main reason is significant visibility improvement and preventing future functionality failures. Cleaning the PCB surface can help you improve the followings:

  • It prevents electrical shortcuts made by leftover solder paste.
  • They are improving PCB signal functionality over leftover flux/solder.
  • Improve the PCB appearance, and prevent dirty spots and marks.
  • Prevent Erosion over the PCB surface. Probably the biggest fear of every hardware maker. A point of Erosion will grow as the PCB is constantly located in a humid environment. Preventing PCB Erosion early could benefit PCB functionality and prevent pcb damage in the long run.

In general, there isn’t a reason why you shouldn’t clean your PCB after soldering. If your PCB was fabricated by a trusted manufacturer such as PCBasic., we can ensure the PCB was properly cleaned before delivery. We use RoHS-certified materials when cleaning the PCB surface mount to ensure compliance and protect your and your customer’s safety.

Detecting PCB contaminations

Early detection of contamination over the PCB surface mount is crucial to prevent further escalation. The most common way to detect contamination is by manual visual review. When the pcb fabrication or pcba production finishes, a professional worker will obverse the board for any possible contamination or leftover flux/solder paste.

There are some other, more professional ways to test PCB and PCBAs for contaminations:

  • 1. FTIR – stands for Fourier Transform Infrared. The technique works on organic materials, using x-ray radiation and sophisticated algorithms. Contamination is detected over the surface mount at quite an early stage.
  • 2. SIR – known as Surface Insulation Resistance is a less common technique due to the time-consuming and unproductive test. This test is done by expensive and large machinery found in very few SMT factories.
  • 3. Ion Chromatography, or IC, is another less common technique separating the ionic materials over the PCB board.

The world is advancing towards smart manufacturing using artificial intelligence and IoT. Visual inspection using AI is a common way to inspect whenever the surface mount requires cleaning.

Methods of cleaning PCB

When it comes to the methods, it depends on the PCB fabrication batch and type of PCBs. We recommend brushing the PCBs manually and visually detecting defects for small quantities. However, for mass production, there are more acceptable methods.

PCB manufacturers will use a solution combined with the ultrasonic technique for mass production. This technique will enable the manufacturer to place multiple PCBs at a high phase. This method is considered highly efficient, ensuring each one gets cleaned in a few seconds. Once the PCBs finish the cleaning, the surface mount cleaning process will move to PCB dry cleaning. Nitrogen gas will ensure no PCBs are left wet.

Once the process is finished, the PCBs will be sent to the next stage of either surface mount PCB assembly or directly sent to the customer.

Surface mount cleaning service

Are you looking to get an online quotation for surface mount cleaning? If you are looking to order PCBs and want to ensure they arrive functional and clean, PCBasic is here to offer you help and support.

Our PCB factory will produce, test, clean and deliver PCBs at the highest quality possible. Using PCBasic SMT and fabrication services, we can ensure a functional, 100% pure PCB delivered to your doorstep.

After every production, the PCB materials are manually and automatically inspected to ensure the quality and functionality of your printed circuit boards.


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