1. PCBA is contaminated PCBA pollutants refer to all substances that can cause damage to PCBA boards, including impurities, dust, surface deposits and ionic compounds. The main reasons for these pollutants are as follows: Soldering is an essential part of PCB assembly work. In order to make solder paste, solder, and solder wire easier to solder, FS Technology will apply a certain amount of flux to the solder joints before soldering. Applying flux to PCBs is a routine operation, but many unprofessional turnkey PCB assembly companies do not clean them, resulting in flux residues remaining on assembled PCB panels. These residual flux will corrode these metal panels. If the storage of the circuit board is not done well, it may even cause the negative ions to react with the water molecules in the air, forming a current, and the PCBA board will be burned. https://www.fs-pcba.com/assembly-pcb/ Received contaminated PCB When you search for circuit board assembly on Google, Google will give you a lot of turnkey PCBA assembly companies, but these companies are not necessarily formal. Many turnkey PCB assembly companies are only responsible for website operations without real production and assembly capabilities. These turnkey assembly companies will find some relatively inexpensive assembly plants to carry out your project. The environment in these assembly plants is very harsh, the air is full of dust, water and solvent vapors, fumes, microscopic organic matter, which explains why the reported loss rate of the goods you receive is so high. When choosing a turnkey PCB assembly company, you must choose a company like FS Technology. If you are not sure how to choose a suitable PCBA company, you can go to FS Technology's knowledge blog to check it out. Assembly companies without a clear code of practice can also lead to board contamination. When workers do manual soldering, they do not wear gloves as required, and the grease and sweat on the surface of the human body will remain on the PCB board, and slight fluctuations will occur during wave soldering. Both PCB and PCB components are metal materials. If they are not stored well, they are easily oxidized by oxygen in the air. In addition, redox reactions accompany the entire PCB assembly line. Hazards of PCBA Pollution The boards didn't fail when you received them from the turnkey PCB assembly company, but some of the boards failed after a while. This is because contamination can cause potential risks to PCBA, the most serious being that organic acids can corrode PCBA. The ions in the residue energize. When there is a potential difference between the two pads, the ions will move with the trend, causing a short circuit and causing the product to fail. Residues can affect the coating effect and can cause problems of non-coating or poor coating. For us, this risk is the most difficult to detect, because it is a long-term imperceptible process that slowly unfolds with changes in air humidity. To this end, FS Technology recommends that you learn some PCBA failure analysis, which can help you fundamentally prevent this kind of thing from happening. Corrosion In the past ten years of assembly experience, FS Technology has found that in addition to carbon, oxygen and lead and tin components, there will be a lot of halogen elements on the surface of the solder joints of the circuit board. In a humid environment, halide ions will use air as a medium and water as an oxidant to form uninterrupted corrosion on solder joints. If you carefully observe the solder joints of the PCBA board, you will find that there are many white lead carbonates on its surface, and a serious hole may have been formed. This situation is more common, but you need special attention when red markings appear on the surface of your circuit board. This is because the halide ions produce Fe3+ after corroding the metal surface. Electromigration There are many reasons for electrical migration. The most common one is that acidic ionic pollutants corrode the copper leads, solder joints and components of the PCB in a humid environment. When your PCBA board main line dendrites, this will cause a partial short circuit in the circuit. damaged PCB Because of the cost problem, we generally do not add silver to the solder in PCB assembly, but many customers will ask us to add it. Electromigration is accelerated by silver ions formed after silver is corroded. Summarize With the advancement of science and technology, human beings are increasingly dependent on electronic products. Qualified turnkey electronic assembly industries generally clean their own products. On the one hand, it is helpful to improve the user experience, and on the other hand, it can protect the environment and human health. As a leader in the PCB assembly industry, FS Technology has always adhered to the principle of customer first, incorporating cleaning into our assembly steps. If you need more professional PCB knowledge, you can go to the FS technology blog, or directly enter the content you need from the link below.
