Complete PCB proofing process

1. print PCB circuit board. Print the drawn circuit board with transfer paper, and pay attention to the slippery side facing yourself. Generally, two circuit boards are printed, that is, two circuit boards are printed on a piece of paper. Among them, the printed circuit board with the best printing effect is selected.
2. Cut aluminum-based copper clad laminate, and make circuit board diagram with photosensitive plate. Aluminum-based copper clad laminate, that is, the circuit board covered with copper film on both sides, cut the copper clad laminate into the size of the circuit board, not too big to save materials.
3. Pretreatment of aluminum-based copper clad laminate. Grind the oxide layer on the surface of aluminum-based copper clad laminate with fine sandpaper to ensure that the carbon powder on the heat transfer paper can be firmly printed on the copper clad laminate when transferring the circuit board. The polished standard is that the board surface is bright and there is no obvious stain.
4. Transfer printing PCB circuit board. Cut the printed circuit board into a suitable size, stick the printed side of the circuit board on the copper clad laminate, put the aluminum-based copper clad laminate into the thermal transfer printer after alignment, and make sure that there is no dislocation of the transfer paper. Generally speaking, after 2-3 times of transfer printing, the circuit board can be firmly transferred to the aluminum-based copper clad laminate. The heat transfer machine has been preheated in advance, and the temperature is set at 160-200 degrees Celsius. Because of the high temperature, pay attention to safety during operation!
5. Corroded circuit board, reflow oven. First, check whether the printed circuit board is completely transferred. If there are a few places that are not transferred properly, you can repair them with a black oily pen. Then it can be corroded. When the exposed copper film on the circuit board is completely corroded, take the circuit board out of the corrosive liquid and clean it, so that a circuit board is corroded. The corrosive liquid is composed of concentrated hydrochloric acid, concentrated hydrogen peroxide and water at a ratio of 1: 2: 3. When preparing the corrosive liquid, water should be drained first, and then concentrated hydrochloric acid and concentrated hydrogen peroxide should be added. If the concentrated hydrochloric acid, concentrated hydrogen peroxide or corrosive liquid accidentally splashes on skin or clothes during operation, it should be cleaned with clean water in time. Because of the strong corrosive solution, it must be used during operation.
Be safe!
6. Drilling the circuit board. Electronic components are to be inserted into the circuit board, so it is necessary to drill the circuit board. Choose different drill pins according to the thickness of the pins of electronic components. When using the drill to drill holes, the circuit board must be held steady, and the speed of the drill should not be too slow. Please watch the operation carefully.
7. Pretreatment of circuit board. After drilling, polish off the toner coated on the circuit board with fine sandpaper, and clean the circuit board with clean water. After the water is dried, it is coated with rosin water on the side with lines. In order to speed up the solidification of rosin, we use a hot air blower to heat the circuit board, and it only takes 2-3 minutes for rosin to solidify.
8. Welding electronic components. After soldering the electronic components on the board, electrify.