2. Put the thermal transfer paper into an ordinary printer, adjust the appropriate printing ratio, and print a black and white PCB diagram. As shown below.
3. Use sandpaper to polish off the oxide layer on the surface of the copper clad laminate, so that the copper clad laminate looks smooth and bright. As shown below.
4. Fix the thermal transfer paper printed with PCB in step 2 on the polished copper clad laminate in step 3, and send it to a thermal transfer machine (common heating iron can also be used instead of the thermal transfer machine) for printing, so that the toner containing PCB is printed on the copper clad laminate by hot pressing, and gradually tear off the thermal transfer paper, as shown in the following figure.
5. Pour the corrosive liquid into the plastic box, then put the corrosive liquid into the copper clad laminate printed with PCB pattern in step 4. After a period of corrosion (the duration varies according to the different concentrations of corrosive liquid), it takes about half an hour to an hour, then pour out the corrosive liquid, take out the corroded copper clad laminate, and gently polish off the carbon powder on the PCB pattern on the copper clad laminate with sandpaper, and you can get a copper circuit wiring exactly like the PCB pattern, as shown in the following figure.
6. Put the copper clad laminate obtained in step 5 into a drilling machine to drill holes one by one according to all the hole positions in the PCB drawing, and finally, the components can be welded correspondingly, and the whole PCB plate-making process is over. As shown below.
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Classification of PCB
According to the circuit layer classification: it is divided into single panel, double panel and multilayer board. Common multi-layer boards are generally 4-layer boards or 6-layer boards, and complex multi-layer boards can reach dozens of layers.
There are three main types of PCB boards:
1, Single-Sided Boards are on the most basic PCB, with parts concentrated on one side and wires concentrated on the other side (the same side as the wires when there are patch components, and the other side of the plug-in components). Because wires only appear on one side, this PCB is called Single-sided.
Because a single board has many strict restrictions on the design of wiring (because there is only one side, the wiring cannot cross and must go around a separate path), only early circuits used this kind of board.
2. Double-Sided Boards This kind of circuit board has wiring on both sides, but to use wires on both sides, it is necessary to have appropriate circuit connections between the two sides. This "bridge" between circuits is called a via. A guide hole is a small hole filled with or coated with metal on the PCB, which can be connected with wires on both sides.
Because the area of the double panel is twice as large as that of the single panel, the double panel solves the difficulty of wiring interleaving in the single panel (it can be connected to the other side through holes), and it is more suitable for more complicated circuits than the single panel.
3. Multi-Layer Boards In order to increase the area that can be wired, multi-layer boards use more single or double-sided wiring boards. A printed circuit board with two sides as the inner layer, two single sides as the outer layer or two double sides as the inner layer and two single sides as the outer layer, which is alternately connected by positioning system and insulating adhesive materials and the conductive patterns are interconnected according to the design requirements, becomes a four-layer and six-layer printed circuit board, also known as a multi-layer printed circuit board.
The number of layers on the board does not mean that there are several independent wiring layers. Under special circumstances, empty layers will be added to control the board thickness. Usually, the number of layers is even and includes the outermost two layers. Most motherboards have a 4-to 8-layer structure, but technically, it is possible to achieve a PCB board with nearly 100 layers. Most large supercomputers use quite a few layers of motherboards, but because this kind of computers can be replaced by clusters of many ordinary computers, the super multi-layer boards have gradually fallen out of use.
Because all layers in PCB are closely combined, it is generally not easy to see the actual number, but if you look closely at the motherboard, you can still see it.
Baidu encyclopedia -PCB (printed circuit board)