PCB production process is more complex, it involves a wider range of processes, from simple machining to complex machining, there are common chemical reactions and photochemical, electrochemical, thermochemical and other processes, computer-aided design CAM and other aspects of knowledge. And in the production process process problems and will meet new problems and part of the problem in the absence of a clear reason for the problem disappeared, due to its production process is a non-continuous assembly line form, any one of the links out of the problem will result in a full line of production or a large number of consequences of the end of life, printed circuit boards, if the end of life is unable to be recycled and reutilized, the process of engineers to work under greater pressure, so many engineers Left the industry to the printed circuit board equipment or material suppliers to do sales and technical service work.
The substrate of the board itself is made of insulating, heat-insulating, and non-bending materials. The tiny lines visible on the surface are made of copper foil, which originally covered the entire board, but was partially etched away during the manufacturing process, leaving behind a mesh of tiny lines. These lines are called conductors (conductor pattern) or wiring, and are used to provide circuit connections to parts on the PCB.
In order to secure the parts to the PCB, we solder their pins directly to the wiring. In the most basic PCB (single panel), the parts are concentrated on one side and the wires on the other. In this case we need to drill holes in the board so that the pins can pass through the board to the other side, so the pins of the parts are soldered to the other side. Because of this, the front and back sides of the PCB are called the Component Side and Solder Side, respectively.
If there are some parts on the head of the PCB, the need for the production can also be removed after the completion of the installation or back, then the installation of the part will be used when the socket (Socket). Since the socket is soldered directly to the board, the part can be removed at will.
If you want to connect two PCBs to each other, we generally use the "gold finger" commonly known as the edge connector (edge connector). The edge connector contains a number of exposed copper pads that are actually part of the PCB wiring. Typically, we connect the edge connector from one PCB to the appropriate slot on the other PCB (commonly called an expansion slot). In computers, such as graphics cards, sound cards, or other similar interface cards, the gold fingers are used to connect to the motherboard.
The green or brown color of the PCB is the color of the solder mask. This layer is an insulating shield that protects the copper wires and prevents parts from being soldered in the wrong place. On top of the solder mask, a silk screen is printed. Often, text and symbols (mostly white) are printed on this screen to indicate the location of each part on the board. The silk screen is also known as a legend.
Printed circuit boards are a complex circuit of copper wires between parts, carefully and neatly planned, etched on a board to provide electronic components in the installation and interconnection of the main support body, is an indispensable part of the basic components of all electronic products.
Printed circuit boards are flat panels made of non-conductive material on which pre-drilled holes are usually designed for mounting chips and other electronic components. The holes in the components help to electronically connect the pre-defined metal paths printed on the board, and the pins of the electronic components are threaded through the PCB and then adhered to the PCB with conductive metal solder strips to form circuits.
In accordance with its application PCB can be divided into single-panel, double-sided boards, four-layer boards above the multilayer boards and flexible boards. Generally speaking, the more complex the function of electronic products, the longer the circuit distance, the more the number of feet of the contact points, the more layers of PCB required, such as high-level consumer electronics, information and communication products, etc.; and flexible boards are mainly used in the need to bend around the product: such as notebook computers, cameras, automotive instrumentation, and so on.