PCB Technical - What electronic product is a printed circuit board

What is a "printed circuit board"?

PCB is the abbreviation for Printed Circuit Board in English. Generally, the conductive pattern made of printed circuits, printed components or a combination of the two on the insulating material according to a predetermined design is called a printed circuit. The conductive pattern that provides electrical connections between components on an insulating substrate is called a printed circuit. In this way, the printed circuit or the finished board of the printed circuit is called a printed circuit board, also called a printed circuit board or a printed circuit board. PCB is almost inseparable from electronic equipment that can be seen, ranging from electronic watches, calculators, general-purpose computers, to computers, communication electronic equipment,

and military weapon systems. As long as there are electronic components such as integrated circuits, the electrical PCB is used for interconnection. It provides mechanical support for the fixed assembly of various electronic components such as integrated circuits, realizes wiring and electrical connection or electrical insulation between various electronic components such as integrated circuits, and provides required electrical characteristics such as characteristic impedance. At the same time, it provides solder mask graphics for automatic soldering; provides identification characters and graphics for component insertion, inspection, and maintenance.

How is PCB made? When you open the keyboard of a general-purpose computer, you can see a piece of soft film (flexible insulating substrate), printed with silver-white (silver paste) conductive patterns and healthy bit patterns. Because the general screen printing method obtains this kind of pattern, this kind of printed circuit board is called flexible silver paste printed circuit board. The printed circuit boards on the various computer motherboards, graphics cards, network cards, modems, sound cards and household appliances that I saw in the Computer City are different. The substrate used in it is made of paper base (usually used for single-sided) or glass cloth base (usually used for double-sided and multilayer), pre-impregnated with phenolic or epoxy resin, and the surface layer is laminated with copper and platinum on one or both sides and then laminated to cure Become. This kind of circuit board copper clad sheet material is called rigid board. If it is made into a printed circuit board, it is called a rigid printed circuit board. A printed circuit board with printed circuit patterns on one side is called a single-sided printed circuit board, and a printed circuit board with printed circuit patterns on both sides and double-sided interconnection through hole metallization is called a double-sided board. If one double-sided as the inner layer, two single-sided as the outer layer, or two double-sided as the inner layer and two single-sided as the outer layer of the printed circuit board, the positioning system and the insulating bonding material alternate together and The printed circuit board with the conductive pattern interconnected according to the design requirements becomes a four-layer or six-layer printed circuit board, also called a multilayer PCB circuit board. There are now more than 100 layers of practical printed circuit boards.

The PCB production process is relatively complex, and it involves a wide range of processes, from simple mechanical processing to complex mechanical processing, common chemical reactions, photochemical, electrochemical, thermochemical and other processes, computer-aided design CAM and many other aspects of knowledge. Moreover, there are many process problems in the production process and new problems will be encountered from time to time. Some of the problems disappear without finding out the cause. Because the production process is a non-continuous assembly line form, any problem in any link will cause the entire line to stop production. Or as a result of a large number of scraps, if printed circuit boards are scrapped, they cannot be recycled and reused. The work pressure of process engineers is relatively high, so many engineers have left the industry and turned to printed circuit board equipment or material vendors to do sales and technical services. .