What about cleaning populated misprinted PCBs (Double-sided misprints)?
Populated misprinted PCBs should never be cleaned in a "spray" style stencil cleaner. The solder balls from side "B" will broadcast throughout the wash chamber and contaminate the components on side "A".
A Smart Sonic Ultrasonic Stencil Cleaner does not spray or circulate the wash solution. The PCB can be oriented with the paste side down. When using an ultrasonic stencil cleaner, the solder paste from side "B" falls freely away from the board by gravity. Components on side "A" are less likely to become contaminated with solder balls when using ultrasonics.
When cleaning populated misprints, frequencies should be kept at 40 KHz or higher (the lower the frequency, the more aggressive the cleaning action) and ultrasonic power (power density) should be kept at a minimum. Because of the efficiency of 440-R SMT Detergent, Smart Sonic does not need to use high-powered ultrasonic energy. Research indicates that ultrasonic power should be kept lower than 10 watts per liter of wash solution. Because of the superior cleaning efficiency of 440-R SMT Detergent, Smart Sonic systems are able to clean effectively at less than 10 watts per liter of wash solution! Assuring the utmost safety for populated assemblies. [Total power of ultrasonic energy (watts) / Total capacity of wash tank solution (liters) = Total watts/liter]