PCB in the circuit board, it refers to the manufacture of PCB materials used, including substrate, substrate parameters, technology and so on. Mainly refers to the base plate, copper foil and adhesives made of copper clad laminate (deposited copper) quality.
PCB Material composition
The main material of PCB is the copper clad laminate (deposited copper) which is made up of base plate, copper foil and adhesive. The substrate is an insulating laminate composed of macromolecule synthetic resin and reinforced material; On the surface of the substrate is covered with a high conductivity, good weldability of pure copper foil, PCB commonly used thickness 35~50/ma; Copper foil covered on the substrate side of the CCL is called a single-sided copper clad laminate, both sides of the substrate covered copper foil CCL said double-sided CCL The copper foil can be firmly covered on the substrate, then by the adhesive to complete. The thickness of common copper clad laminate is 1. 0mm, 1. 5mm and 2. 0mm three kinds.
PCB is more and more widely used, because it has a lot of unique advantages, trichosanthes as follows: can be high-density. For decades, the high density of PCB has been developed with the improvement of integrated circuit integration and installation technology. High reliability. Through a series of inspection, PCB testing and aging tests can ensure that the PCB long-term (use, generally for 20) and reliable work. can be designed. PCB Performance (electrical, physical, chemical, mechanical, etc.) requirements, can be designed through standardization, standardization, etc. to achieve PCB design, short time, high efficiency. can be productive. PCB The use of modern management, can be standardized, scale (volume), automation and other production, to ensure consistency of product quality. Testability. Set up a relatively complete test methods, testing standards, a variety of testing equipment and instruments to detect and identify the PCB product eligibility and service life. can be assembled. PCB products are not only convenient for a variety of components standardized assembly, and can be automated, large-scale production. At the same time, PCB and various components assembly parts can also be assembled to form larger parts, systems, until the machine. Maintainability。 As PCB products and components are assembled in a standardized design and large-scale production, and therefore, these components are also standardized. Therefore, once the system fails, can quickly, easily, flexibly to replace, quickly restore service system work. Of course, there are more examples. such as the miniaturization of the system, lightweight, high-speed signal transmission and so on.
Single panel (single-sided boards) on the most basic PCB, the parts are concentrated in one side, the wire is concentrated on the other side (there are SMD components and the wire for the same side, the plug-in device on the other side). Because the wire only appears in one side, PCB so this kind of PCB is called Single-sided Board (single-sided). Because the single panel in the design line has many stringent restrictions (because only one side, the wiring between the intersection and must be around the path alone), PCB so only the early circuit to use this kind of board.
Double-sided Board (double-sided boards) This circuit board on both sides of the wiring, but to use the two sides of the wire, must be on both sides of the appropriate circuit connection before the line. The "bridge" between the circuits is called a guide hole (via). The guide hole is on the PCB, PCB fills or spreads the metal the small hole, it may connect with the two sides the conductor. Because the area of the double-sided board is larger than the single panel, the double panel solves the difficulty of wiring interleaving in Single panel (can pass through Kong to the other side), PCB it is more suitable to use in the circuit than the single panel more complex.