A Feasible Method to Determine the Number of PCB Layers

Would you like to verify your PCB layer count, is it a 4-layer board as required or just a double-sided board? Is there any way to quickly verify without going to the workstation? Listed below are several easy-to-use methods for determining the number of layers in a PCB. 

Although the layers of the PCB are tightly stacked, they can still be discerned by looking closely at the edges of the board.

Looking closely, we can see that one or more layers of white matter are sandwiched between the boards, which are actually insulating layers between every two layers of boards to avoid short circuits between different PCB layers.

For multilayer printed circuit boards, more layers of insulation are sandwiched between the copper layers of the PCB. The number of layers of the PCB can be known by counting the number of insulating layers with the naked eye.

Determine the number of PCB layers by checking for vias or blind vias. The principle is mainly based on the application of technology in the circuit connection of multi-layer circuit boards. By identifying the vias, we were able to determine the number of PCB layers.

On a single-sided PCB, the parts are concentrated on one side and the pins are concentrated on the other side. If you want to use a multi-layer PCB, you need to punch holes in the board so that the component pins can pass through the board to the other side, and we can see that the pins of the part are soldered to the other side.

For example, on a 4-layer PCB board, the signal lines need to go on the 1st (TOP) and 4th (BOT) layers, the internal PCB layers play other roles (ground and power layers), and the signal layers are placed on both sides of GND & Vcc for the purpose of preventing mutual interference. If some vias appear on the top layer, but cannot be found on the bottom layer, it means that the number of PCB layers is 6 or more. If the same vias can be found on both sides of the PCB board, it is generally a 4-layer board.

However, more sophisticated buried via technology is currently used in circuit board fabrication, this type of via is only used to connect a few pairs of inner layers and is not visible on the surface of the PCB. Therefore, determining the number of board layers by inspecting via is easy to use, but has limitations.

To be precise, this is not a method, but a practical experience, but this is what we think is the most accurate. The number of PCB layers can be determined according to the traces and components of the PCB board used in a certain industry.

They are traceable because, even with hardware upgrades so fast, few designers have the ability to recreate the design rules of those widely used electronics.

The above briefly introduces the method of identifying the number of PCB layers. If you want to customize a multi-layer PCB, please contact us.

Singo is a professional custom PCB manufacturer. Our company has been specialized in electronic PCB assembly. Mainly engaged in PCB assembly and OEM/ODM electronic manufacturing services since 2006. The products involve home appliances, digital products, industrial control, and medical equipment. After years of hard work, we have established long-term cooperative relations with some well-known international enterprises.