Multilayer PCB is the result of the development of electronic information technology to high speed, multi-function, large capacity, small volume, thin and lightweight. For the production of PCB board, the more layers, the more programs will be made, the failure rate will increase correspondingly, and the corresponding cost will be higher. Therefore, multilayer boards are commonly used in advanced circuits. Four-layer board is a common multi-layer PCB, so what are the four layers of four-layer board? Next, Shenzhen PCB manufacturer kingford will introduce you.
The four layers of the PCB board are divided into signal layer (top layer), signal layer (bottom layer), power layer (middle layer) and formation (middle layer).
Typically, components are placed on the top layer of the PCB, so the top layer is also referred to as the component surface; The bottom is generally used for welding, so the bottom is also called the welding surface. In the case of patch components, components can be placed on both upper and lower layers.
Four-layer PCB board layout:
1. Lay multiple GND lines respectively on the first layer in the middle. Several lines can be laid, but do not divide each layer of copper; The second layer of VCC copper in the middle has a plurality of power supplies laid separately. A small number of lines can be laid, but do not divide each layer.
2. Wiring has four layers, usually the TOP LAYER, Buttom Layer, VCC and GND. Generally, through holes, buried holes, blind holes and other ways to connect between layers, more than double-layer PCB board. In addition, VCC and GND layers should try not to use signal lines.
2. Common causes of PCB board cable breakage
To make a complete PCB, need to go through many complex processes. If there are some operational errors in the PCB production process, it will lead to quality problems in the final finished board, which does not meet the product requirements. PCB breaking problem will affect the realization of PCB function. Next, kingford, a professional PCB board factory in Shenzhen, introduces the common causes of PCB board breakage.
Common causes of PCB wire breakage
1, the film process: the film is not firm, there are bubbles. If the film is wet, there will be waste contamination.
2. Exposure process: the negative film has problems caused by scratches or garbage, including exposure machine problems, insufficient exposure parts, etc.
3. Development process: The development is ambiguous.
4, etching process: nozzle pressure is too high, etching time is too long.
5, plating problems: plating uneven or surface adsorption force.
What is the cause of PCB board break? First of all, look at the form of broken wire. By analyzing the form of broken wire, find out the process of PCB board broken wire caused by problems, and then investigate the possible causes step by step in the production process.
kingford is a Circuit board manufacturer specializing in the manufacture of printed circuit boards. It has been dedicated to the production of single, double-sided and multi-layer circuit boards for 20 years. We can provide PCB proofing and mass production services such as FR4 hard board, FPC soft board, HDI board and metal substrate.