In the field of precision electronic cleaning, aqueous cleaning fluids are favored for their environmental protection and high efficiency. However, due to their direct contact with circuit boards and chips, improper use can easily cause damage. Risk avoidance requires starting from multiple links such as ingredient control, cleaning process, and drying treatment to ensure the safety of electronic components in all aspects.
The composition of aqueous cleaning fluids directly determines their safety for electronic components. Ordinary water contains mineral ions, which may cause short circuits or corrosion. Therefore, aqueous cleaning fluids must use deionized water as the base liquid to eliminate the potential threat of conductive ions from the source. At the same time, additives must be carefully selected to avoid the use of strong acid and alkali components. For example, some aqueous cleaning fluids add mild surfactants, which can reduce surface tension and enhance cleaning effects without corroding metal circuits; adding corrosion inhibitors can form a protective film on the metal surface to prevent copper circuit oxidation, ensure that the pH value of the cleaning fluid is maintained in the neutral range of 6.5-7.5, and reduce chemical erosion of solder joints and insulating coatings.
Pretreatment and preparation before precision electronic cleaning are key steps to reduce the risk of damage. Before using aqueous cleaning fluid, make sure that the circuit board is completely powered off and fully discharged to avoid short circuits caused by live operation. For removable circuit boards, water-sensitive components, such as unsealed electrolytic capacitors, need to be removed in advance. At the same time, check whether there are cracks or damage on the surface of the circuit board to prevent the cleaning fluid from penetrating into the interior and causing secondary damage. In addition, operators need to wear anti-static gloves and wristbands and operate on an anti-static workbench to avoid static electricity from damaging sensitive devices such as chips.
Standardized cleaning operation procedures are the core of protecting electronic components. When using the immersion method, the immersion time must be strictly controlled to avoid long-term immersion causing water to penetrate into the gaps of components. For complex circuit boards, ultrasonic assisted cleaning can be used, but the power and frequency must be accurately adjusted to prevent the vibration amplitude from shaking off tiny components or damaging fragile chip pins. If spray cleaning is used, ensure that the nozzle is kept at a suitable distance and angle from the circuit board to avoid excessive water flow impact and washing away the patch components. During the cleaning process, a dedicated cleaning container should be used to prevent the container material from reacting with the cleaning fluid to produce impurities.
Drying after cleaning directly affects the performance and life of electronic components. If the residual moisture in the aqueous cleaning fluid is not removed in time, it may cause rust on the solder joints and short circuits. Therefore, drying is required immediately after cleaning. First, compressed dry air can be blown along the surface of the circuit board at a 45-degree angle to quickly remove most of the surface moisture, and then the circuit board is placed in a constant temperature drying oven with the temperature set between 40-60℃ and baked for 1-2 hours to ensure that the moisture is completely evaporated. For precision components such as chips, vacuum drying can be used to accelerate the volatilization of moisture while avoiding thermal damage to the components caused by high temperature. During the drying process, the state of the circuit board needs to be checked regularly to prevent local corrosion due to uneven drying.
Avoiding secondary contamination is also a key issue to pay attention to when using aqueous cleaning fluids. The cleaning environment should be kept dust-free, and dust covers should be used to cover the uncleaned and cleaned circuit boards to prevent dust, fibers and other particulate contaminants from adhering to the wet circuit board surface. Cleaning tools must be dedicated and clean, and avoid using brushes and sponges that have been reused and not thoroughly cleaned to prevent residual impurities from scratching the surface of the circuit board or bringing in new contaminants. At the same time, the cleaning fluid needs to be replaced regularly to avoid re-contamination of the circuit board during the cleaning process due to excessive stain concentration in the cleaning fluid.
Compatibility testing of precision electronic cleaning and electronic components is essential. Before large-scale cleaning, select discarded circuit boards or components for small-scale testing. Apply the aqueous cleaning fluid to the edges of the circuit board, solder joints, chip packaging and other parts to observe whether there are coating swelling, metal discoloration, loose solder joints and other phenomena. If abnormalities are found, the cleaning fluid must be stopped immediately, and the cleaning fluid formula must be re-evaluated or the product must be replaced to ensure that no damage is caused to precision electronic components during formal cleaning.
Professional training and standardized management of operators are important guarantees to avoid damage. Enterprises need to formulate detailed standard operating procedures (SOPs) for the use of aqueous cleaning fluids, clarifying key points such as cleaning fluid ratios, operating steps, and drying parameters. Operators should be trained regularly to enable them to master the characteristics of cleaning fluids, equipment usage methods, and abnormal situation handling measures. A quality supervision mechanism is established to conduct strict inspections on the cleaned circuit boards. The solder joint status is checked through a magnifying glass and the circuit insulation is tested using an insulation resistance tester to ensure that every cleaned circuit board and chip meets the quality requirements.
