How to clean your pcb properly with ultrasonic(3)– What things you should caution ?
Pay attention to the following aspects when you operate an ultrasonic PCB cleaner :
(1) Resonance phenomenon may occur for ceramic package integrated circuits, and other forms of packaging middle cavity. It may make the interior of the welded gold wire snapped off .
(2) If the power of ultrasonic cleaning is too high, the time is too long, it may cause some damage to the fragile part.
(3) Unexpected resonance may cause some broken solder joint failure. (4) It may have environmental issues, such as the strong noise, volatile solvents.
(5) Ensure reliable ultrasonic cleaning confidential grounded, otherwise static electricity generated there may damage components on the circuit board. But so far it seems there is no clear evidence that ultrasonic cleaning is not available for electronics assembly processes.
(6) Don’t directly put the circuit board on the bottom of the ultrasonic cleaning tank, otherwise it will hinder the ultrasonic vibration, which seriously affect the ultrasonic cleaning. At a distance of about 5 cm between the board and the bottom of the tank .
(7) The Circuit board does not exceed 70% of the cross-sectional area cleaning trough, otherwise it will affect the ultrasonic cleaning.
(8) Surface of alcohol exceed the top of pcb at least about 2. 5 cm.
(9) The pcb must be suspended with the cleaning basket. The basket can not be made of plastic or other flexible material to avoid absorption of ultrasound. Preferably stainless steel baskets, but the grid as large as possible, at least 5 mm or more, so as not to shield ultrasonic influence of ultrasonic cleaning.
(10) A single-layer placed is the best way for pcb , otherwise the upper pcb cleaning dirt will fall down and pollute the lower pcb .
(11)It’s better to keep proper space between the circuit board, about 5 cm, to obtain the best washing effect and prevent cross-contamination. The circuit board and the groove wall of the cleaning tank is preferably maintained from about 1 cm.
(12)Be careful the temperature of the flammable solvent , avoiding the high temperature and cause fire.
(13) A cleaning basket fitted with a circuit board when loading and unloading the cleaning tank, be sure to slow, not too perturbed alcohol solvent, otherwise it will cause a short ultrasonic weaken or even disappear.