Process flow of PCB
Visit:1582 Date:2020-08-24

1. Print the circuit board. Print out the drawn circuit board with transfer paper, pay attention to the slippery side facing you, generally print two circuit boards, that is, print two circuit boards on one sheet. Choose the circuit board with the best printing effect among them.
2. Cut the copper clad laminate and use the photosensitive board to make the whole process diagram of the circuit board. Copper clad laminate, that is, a circuit board covered with copper films on both sides, cut the copper clad laminate to the size of the circuit board, not too large to save materials.
3. Pretreatment of copper clad laminate. Use fine sandpaper to polish away the oxide layer on the surface of the copper clad laminate to ensure that the carbon powder on the thermal transfer paper can be firmly printed on the copper clad laminate when transferring the circuit board. The standard for polishing is that the board surface is bright without obvious Stains.
4. Transfer circuit board. Cut the printed circuit board to a suitable size, and paste the printed circuit board on the copper clad laminate. After alignment, put the copper clad laminate into the heat transfer machine. Make sure that the transfer paper is not misaligned. Generally, after 2-3 transfers, the circuit board can be transferred firmly on the copper clad laminate. The heat transfer machine has been preheated in advance, and the temperature is set at 160-200 degrees Celsius. Due to the high temperature, pay attention to safety during operation!
5. Corrosion circuit board, reflow soldering machine. First check whether the printed circuit board is completely transferred. If there are a few areas that have not been transferred, use a black oil-based pen to repair. Then it can be corroded. When the exposed copper film on the circuit board is completely corroded, the circuit board is removed from the corrosive solution and cleaned, so that a circuit board is corroded. The composition of the corrosive solution is concentrated hydrochloric acid, concentrated hydrogen peroxide, and water in a ratio of 1:2:3. When preparing the corrosive solution, discharge water first, and then add concentrated hydrochloric acid and concentrated hydrogen peroxide. If the concentrated hydrochloric acid, concentrated hydrogen peroxide or corrosive solution is not Be careful of splashing on the skin or clothing, and wash it with clean water in time. As a strong corrosive solution is used, pay attention to safety during operation!
6. Circuit board drilling. The circuit board needs to be inserted with electronic components, so it is necessary to drill the circuit board. Choose different drill bits according to the thickness of the electronic component pins. When using the drill to drill, the circuit board must be pressed firmly. The drill speed cannot be too slow. Please carefully watch the operator's operation.
7. Circuit board pretreatment. After drilling, use fine sandpaper to polish off the toner on the circuit board, and clean the circuit board with water. After the water dries, apply rosin to the side with the circuit. In order to accelerate the solidification of the rosin, we use a hot air blower to heat the circuit board, and the rosin can solidify in 2-3 minutes.
8. Welding electronic components. After soldering the electronic components on the board, power on.