How to clean your pcb properly with ultrasonic(2)–7 steps to tell you how to clean your pcb ?

7  steps

1. First, the pcb completely immersed in the cleaning tank filled with alcohol, after the completion of the circuit board soldering, soak 5min.
2. Pour the amount of alcohol into the ultrasonic cleaning tank, the alcohol from the wash liquid from the top edge of the tank in less than 5 cm, and then turn the power on, ultrasonic vibration 5 ~ 15 mins, to eliminate the alcohol solvent retraction gases. Because retraction of the gas will destroy the ultrasonic cavitation, thereby reducing the efficiency of ultrasonic cleaning.
   
3. Put the circuit board into the cleaning basket after soaking , slowly into the ultrasonic cleaning tank , the presetting time is 5-10 mins, the frequency selection 40kH z, the output power is less than 30W / L.
4. Remove the PCB, observing the cleaning results, depending on the circuit board cleanliness then ultrasonically cleaned about 1 min ~ 5min. 
5. Surface cleanliness was observed after ultrasonic cleaning circuit boards, such as there are still stubborn dirt, using anti-static brush to brush clean. 
6. Slowly bring the cleaning basket up and placing into another tank filled with alcohol, gently shake the board, rinse clean. 
7. Take the circuit board out, to dry naturally.

Pay attention to the following aspects when ultrasonic cleaning:

(1) 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 .

(2) The Circuit board does not exceed 70% of the cross-sectional area cleaning trough, otherwise it will affect the ultrasonic cleaning.

(3) Surface of alcohol exceed the top of pcb at least about 2. 5 cm.

(4) 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.

(5) A single-layer placed is the best way for pcb , otherwise the upper pcb cleaning dirt will fall down and pollute the lower pcb .
(6)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.

(7)Be careful the temperature of the flammable solvent , avoiding the high temperature and cause fire.

(8) 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.