What is a printed circuit board?

Print the electricity. Road Board (Printed Circuit Board, PCB), refers to the insulating substrate, selectively processing and mounting holes, connect wires and welding plate assembly of electronic components, in order to realize the components between the electrical connection in the assembly panel. The printed circuit board is one of the most important components in electronics, from home appliances, communication equipment, weapons equipment to aerospace equipment, and any electronic equipment can't be separated from the printed circuit board. In the development of electronic products, the design, documentation and manufacture of printed plates are the main factors that influence the success of the product. It can be said that the design and manufacturing quality of the printing plate directly affects the quality and cost of the whole product. Printed circuit technology is the development direction of high density, high precision, high reliability, large area, fine lines, it depends on the printing technology, chemical technology, precision machining, optical technology, CAD technology, and constantly improve and development of new materials and technology.

A qualified by the bonding pad printed circuit boards, via, installing hole, positioning hole, printing line, components surface, welding, resistance welding layer and screen printing and so on, has the dual role of conductive lines and insulating base.

Printed circuit board

(1) the welding plate.

It is also referred to as the connecting disk, which refers to the metal part of the printed wire in the surrounding area of the soldering hole for the welding of the external lead wire, which is usually obtained through the treatment of the copper plate. Some of the soldering plates on the PCB are formed by coating the copper foil with a coating of resistance flux. Some of the soldering disks on PCB are used in such measures as dip silver, dip tin, dip - plating tin alloy etc. The size and shape of the solder plate have a direct impact on the quality of the solder joints and the quality of the PCB.

(2) the hole.

A hole is a metal hole that is connected to the upper and lower layers of a PCB, usually filled with metal or coated with metal. The process of coating the hole with metal is known as porthole metallization. The overhole can be used as a solder plate or as a connection hole, depending on its role in the circuit.

(3) mounting hole.

The hole is used for fixing large components and installing PCB holes. The actual size of the hole is determined.

(4) locating hole.

Positioning hole is a small hole used for PCB processing and detection and locating. It usually adopts three hole positioning method. The size of aperture should be determined by the assembly process. Sometimes it can be replaced by mounting holes.

(5) production line.

Printing line is essentially components connection circuit on PCB, it is the copper foil on the copper clad, according to the requirement of the actual circuit connection through a series of etching processing and network of fine lines. The printed lines on the finished PCB are usually coated with a layer of green or brown blocking flux to prevent oxidation and rust.

(6) components surface.

The component surface is also called component assembly surface, which is used to install components on PCB. The one side of the non-printed line (copper foil) on the single-sided PCB is the component surface; On the double-sided PCB, the image and character of the components are printed on the surface of the components.

(7) welding surface.

The welding surface, also known as the printed surface, is a part of PCB that is used to weld the components of the components, usually without any marks.

(8) resistance welding layer.

As the name implies, the resistance layer is the layer that blocks the welding, and the green (or brown) layer on the PCB is the protective layer of insulation. The resistance layer can protect the copper wire from oxidation and prevent the components from being soldered to the wrong place.

(9) the silk screen.

The screen printing layer is used to mark the position of the components on the PCB, mostly white, with words and symbols on the resistance welding layer of PCB. Because the manufacturing process USES the silk printing method, hence the silk printing layer.