PCB Technical - Detailed explanation of PCB cleaning process

Printed Circuit Board(PCB) needs to be cleaned many times. Then, which links need to be cleaned and how to wash it? Next, the cleaning process summarized by electrician's house is summarized for your reference.

1. Cutting: cutting large plate into small pieces required.
   Plate washing: clean and air dry the dust and impurities on the Printed Circuit Boardmachine.

   
   

2. Inner dry film: a layer of gelatin is pasted on the copper foil, and then the circuit diagram is formed after the counter exposure and development of black film.
   Chemical cleaning:
   (1) Remove the oxygen compounds and garbage on the surface of Cu; slander the surface of Cu to strengthen the bonding force between the surface of Cu and gelatin.
   (2) Process: degreasing - water washing - micro erosion - high pressure water washing - circulating water washing - water absorption - strong wind drying - hot air drying.
   (3) The influencing factors of plate washing are: degreasing speed, degreasing agent liquid concentration, micro corrosion temperature, total acidity, Cu2 + liquid concentration, pressure and speed.
   (4) Easy to sprout and lack: open circuit - cleaning effect is very poor, resulting in rejection of film; short circuit - cleaning is not clean germinating waste.

   
   

3. Copper deposition and plate electricity

   
   

4. Outer dry film

Printed Circuit Board(PCB)

5. Graphic plating: implement in hole and circuit to meet the requirements of copper plating thickness.
(1) Degreasing: removing oxygen layer and surface pollutants on the board surface;
(2) Acid leaching: removal of pollutants from pre-treatment and copper cylinder;

6. Printed Circuit Boardelectrogold:
(1) Degreasing: remove grease and oxygenates on the surface of circuit diagram to keep copper surface clean.

7. Wet green oil:
(1) Pre treatment: remove the oxygen film on the surface and roughen the surface to strengthen the bonding force between green oil and Printed Circuit Board surface.

8. Tin spraying process:
(1) Hot water washing: cleaning the surface of circuit board dirt and local ions;
(2) Scrubbing: further cleaning the residual debris left on the circuit board surface.

9. Gold deposition process:
(1) Acid degreasing: remove mild grease and oxygenates on the surface of copper, so as to activate and clean the surface, and form the appearance suitable for nickel plating and gold plating.

10. Shape processing
(1) Plate washing: remove surface pollutants and dust. 11. Netek copper surface disposal.
(2) Degreasing: remove grease and oxygenates on the surface of circuit diagram to keep copper surface clean.

The steps of copper surface finishing are as follows:

1. Dry film pressing

2. Before oxygenation of inner layer

3. After drilling (remove the glue residue, clean up the colloidal body that sprouts during the drilling process to make it coarsened and clean) (mechanical grinding plate: clean the hole with vibration wave which can cause super hearing, and clean the copper powder and adhesive particles in the hole completely)

4. Before chemical copper

5. Before copper plating

6. Before green paint

7. Before tin spraying (or other welding pad disposal process)

8. Before nickel plating on gold finger

Pre treatment of secondary copper:

degreasing - water washing - micro etching - water washing - acid leaching - copper plating - water washing. All the impurities such as oxygenation, fingerprints and micro objects that may be left on the board surface during the previous process of outer circuit manufacturing are removed. And with the surface activation, so that copper plating adhesion is good.

Before shipment, a cleaning should be carried out, and the ion pollution should be removed.