PCB Technical - pcba board ultrasonic cleaning machine, water-based cleaning

Types, sources and hazards of contaminants that PCBA boards are not cleaned:

The adhesion mechanism of contaminants on PCBA board:

From a microscopic point of view, the bonding or attachment between matter and matter mainly depends on the combination of atoms and atoms or molecules and molecules. The former is called "chemical bond" and the latter is called "physical bond". Sometimes these two bonds Can be combined and coexist with each other. In addition, the "mechanical anchoring effect" formed by the surface roughness promotes the adhesion of contaminants.

The problem of PCBA failure caused by contaminants attached to the PCBA board:

1. PCBA circuit board corrosion

PCBA assembly uses iron substrate bottom lead foot components. Due to the lack of solder bottom coverage, the iron substrate quickly produces Fe3+ under the corrosion of halogen ions and moisture, which makes the board surface red. In addition, in a humid environment, acidic ionic pollutants can directly corrode copper leads, solder joints and components, causing circuit failure.

2. PCBA circuit board electronic migration

If there is ion contamination on the PCBA surface, electromigration is prone to occur, and the ionized metal moves between the opposite electrodes and reduces to the original metal at the reverse end, resulting in a dendritic phenomenon called dendritic distribution, (dendritic, Dendrites, tin whiskers), the growth of dendrites may cause local short circuits in the circuit.

3. Poor electrical contact on PCBA board

In the PCBA assembly process, some resins such as rosin residues often contaminate the gold fingers or other connectors. When the PCBA is working hot or in a hot climate, the residues will become sticky and easy to absorb dust or impurities, which will increase the contact resistance. Large or even open circuit failure. The corrosion of the nickel layer on the PCB surface pad in the BGA solder joint and the presence of the phosphorus-rich layer on the surface of the nickel layer reduce the mechanical bonding strength of the solder joint and the pad. Cracks occur when subjected to normal stress, resulting in point contact failure.

PCBA ultrasonic cleaning cleaning process mechanism:

The cleaning mechanism is mainly to destroy the chemical bond or physical bond between the pollutant and the substrate. The purpose of separating pollutants from the substrate is mainly achieved through the wetting, dissolving, emulsifying, saponification, chelation and other functions of the cleaning agent.

The corresponding cleaning method of water-based cleaning agent:

Cleaning method corresponding to PCBA water-based cleaning agent

1. The cleaning temperature is generally between 60°C and 70°C.

The higher the cleaning temperature, the higher the cleaning performance of solder. Increasing the temperature above the solder softening point can improve the cleaning effect.

The required temperature can be changed. However, it must be confirmed in advance when the temperature is above 70°C.

2. The cleaning time and protection rinse time only need to be rinsed for 1 to 5 minutes.

When cleaning the small gaps on the back of similar surface mounted parts, it should be cleaned for more than 10 minutes.

Improve cleaning performance (shorten cleaning time) by improving cleaning jigs and fixtures.

3. The final rinse (purified water rinse) time is based on the tank capacity (L) ÷ pure water supply (L/min) * 2.

For example: the tank capacity is 10L, the pure water supply is 2L/min, and the final rinse (purified water rinse) time is 10 minutes.

However, it does not include the use of multiple tanks to maintain the water quality in the final tank (pure water).

The cleaning effect of the cleaning method corresponding to the water-based cleaning agent:

What are the summary of PCBA ultrasonic cleaning machine and PCBA water-based cleaning process:

1. Water-based cleaning agent has super-strong dissolving and cleaning power, which is incomparable to traditional solvent cleaning agents, and can be applied to all types of flux residue cleaning

2. Fully meet the requirements of current environmental protection regulations such as ROHS, REACH, SONY00259, HF, etc.

3. The wide process window is not affected by its cleaning methods and equipment, and fully meets the cleaning requirements of various manufacturers.

4. Completely eliminate fire safety hazards. 5. Improve the affinity between the environment and people (no pollution to the environment, harmless to the human body).

6. The water-based cleaning agent is non-volatile and can be recycled, which greatly reduces the cost of production and improves market competitiveness.

In summary, the equipment PCBA water cleaning machine and water-based cleaning agent series products of the PCBA factory can not only provide you with effective, safe and best cleaning agents, but also help you find the best cleaning process solutions for you. Reduce operating costs and improve market competitiveness! Help you achieve a comprehensive upgrade of equipment, technology, and materials!