When pressing, PP and copper foil are added to both sides of the double-sided board, and pressed into a multi-layer board by high temperature and high pressure. In short, a four-layer board has an inner layer. In terms of process, some circuitry will be etched and pressed through the inner layers. The double-sided panel can be directly cut and drilled after leaving the factory.
A four-layer board refers to a printed circuit board. The PCB is made of four layers of glass fiber, which can reduce the cost of the PCB, but it is very inefficient.
Although it is difficult to get a four-layer PCB by observing the cross section of the PCB, few people have such vision. However, four-layer boards can be identified by looking at the pilot holes. If the same guide holes can be found on both sides of the PCB, or the motherboard or display card is facing the light source, if the position of the guide holes cannot transmit light, it is a four-layer board.
The four-layer board is made by pressing on the basis of double-sided boards. When pressing, PP and copper foil are added to both sides of the double-sided board, and then the multi-layer board is formed by high temperature and high pressure pressing. In short, a four-layer board has an inner layer. In terms of process, some circuitry will be etched through the inner layers and then pressed. The double-sided panel can be directly cut and drilled after leaving the factory.
