PCB (printed circuit board), or printed circuit board, is one of the important parts of electronic industry. Almost every kind of electronic equipment, from electronic watches and calculators to computers, communication electronic equipment and military weapon systems, as long as there are integrated circuits and other electronic components, in order to make the electrical interconnection between the components, printed circuit boards must be used. Printed circuit board (PCB) is composed of insulating base plate, connecting wire and pad for assembling and welding electronic components, which has the dual functions of conductive circuit and insulating base plate. It can replace the complex wiring and realize the electrical connection between the components in the circuit. It not only simplifies the assembly and welding of electronic products, reduces the workload of wiring in the traditional way and greatly reduces the labor intensity of workers, but also reduces the volume of the whole machine, reduces the cost of products and improves the quality and reliability of electronic equipment. Printed circuit board has good product consistency. It can adopt standardized design, which is conducive to mechanization and automation in the production process. At the same time, the whole PCB after assembly and debugging can be used as an independent spare part to facilitate the exchange and maintenance of the whole product. At present, printed circuit board has been widely used in the production of electronic products.
The first used of PCB is paper-based copper printing board. Since the semiconductor transistor appeared in the 1950s, the demand for printed boards has risen sharply. Especially with the rapid development and wide application of integrated circuits, the volume of electronic equipment is smaller and smaller, and the circuit wiring density and difficulty are becoming more and more difficult. Therefore, the printed boards should be updated continuously. At present, the variety of printed boards has been developed from single panel to double-sided board, multilayer board and flexible board; the structure and quality have also developed to ultra-high density, miniaturization and high reliability; new design methods, design supplies, board making materials and plate making technology are emerging. In recent years, the application software of various CAD printed circuit boards has been widely used in the industry. In the specialized PCB manufacturers, the mechanization and automation production have completely replaced manual operation.
Previous：already is the first one