The advantage of water cleaning is that the cleaning medium of water cleaning is generally non-toxic, does not endanger the health of workers, is non-flammable, non-explosive, and has good safety. Water cleaning has a good cleaning effect on particulate matter, rosin flux, water-soluble pollutants and polar pollutants: water cleaning has good compatibility with packaging materials of components and PCB materials, and will not make rubber parts and coatings Swells without cracking, leaving markings and symbols on part surfaces clear and intact without being washed away. Therefore, water cleaning is one of the main processes of non-ODS cleaning.
The disadvantage of water washing is that the investment in the whole equipment is large, and it also needs to invest in water production equipment for pure water or deionized water. In addition, it is not suitable for non-airtight devices, such as adjustable potentiometers, inductors, switches, etc. Water vapor entering the device is not easy to discharge, and even damages the ring element.
Washing technology can be divided into pure water washing and water plus surfactant washing. A typical PCBA process flow is as follows: water + surfactant → water → pure water → ultrapure water → hot air washing → rinsing → drying.
Generally, an ultrasonic device is added in the cleaning stage, and an air knife (nozzle) device is also added in the cleaning stage in addition to the ultrasonic device. The water temperature should be controlled at 60-70°C, the water quality should be very high, and the resistivity should be 8-18mq? cm. This alternative technology is suitable for SMT chip processing plants that have high requirements for mass production and product reliability. For small batch cleaning, small cleaning equipment can be select.
Hope the above content can help you!
