PCBA Tech - What are the cleaning solvents for PCBA circuit board surface?

What are the cleaning solvents for PCBA circuit board surface?

In the PCBA processing process, the use of solder paste and flux will produce residual substances. The flux residues will gradually harden over time and form corrosives such as metal halides, which will be detrimental to the reliability and service life of the PCB. Therefore, after the PCBA processing is completed, it is necessary to completely remove the residual flux, solder and other contaminants on the PCB board to keep the surface of the PCBA board clean and tidy. There are many kinds of cleaning solvents for the PCBA circuit board surface on the market, so how do we choose Woolen cloth?

1. Solvent cleaning agent

Solvent cleaning agents can be divided into hydrocarbon solvents, halogenated solvents, and fluorinated solvents. Solvent-based cleaning agents are self-cleaning and low-residue cleaning agents. The disadvantage is that they are easy to evaporate and volatile, and require special attention in storage. Due to the requirements of environmental protection policies, halogenated solvents and fluorinated solvents have been less used in recent years. When using hydrocarbon cleaning agents, it is necessary to pay attention to the fire prevention measures of the machine and the environment. At the same time, the leak-proof treatment of volatile organic compounds must be considered. After these conditions are good, hydrocarbon solvent cleaning agents can be used in small-batch PCBA proofing. Hydrocarbon cleaning agents have a better effect on some rosin-type and some no-clean flux residues, oil stains, and dirt.

2. Water-based cleaning agent

Water-based cleaning agents can be used in most scenarios, but when choosing water-based cleaning agents, you must consider the limitations of circuit board surface, metalization and compatibility, including lead oxide reactants, white metal, yellow metal, and ink markings. Compatibility with the coating material, followed by the size, spacing, and complexity of the assembly. Different types of flux residues have different compositions, and the cleaning materials of water-based cleaners have different ability to remove solder residues. At the same time, the water-based cleaning agent cleaning process is also the atmosphere ultrasonic cleaning process and the spray cleaning process. In the spray cleaning attack, the tolerance to foam is lower, and it requires no foam or minimal foam and can quickly dissipate.

When we know the composition of the residue remaining on the PCBA circuit board, we can choose whether to use a solvent cleaner or a water-based cleaner according to actual needs. When meeting the cleaning conditions, we also need to consider environmental issues.