Why should traces and drill holes be kept away from the edge of the PCB board?

There are several main reasons for keeping traces and drill holes away from the edges of a PCB:

Preventing edge damage: Placing traces and drill holes near the edges of a PCB can lead to edge damage. The edges of PCBs are susceptible to mechanical stress and external environmental factors such as compression, shearing, bending, or corrosion. Keeping traces and drill holes away from the edges reduces the vulnerability of these areas and lowers the risk of edge damage.

Improving reliability: In the edge area of a PCB, traces and drill holes are more prone to be affected by concentrated mechanical stress and the instability of the physical environment, including stress, vibration, or temperature variations. Keeping them away from the edges reduces the impact of these unstable factors on traces and drill holes, thereby improving the reliability and stability of the PCB.

Avoiding electromagnetic interference: The edge area is typically more susceptible to external electromagnetic interference. Keeping traces and drill holes away from the edges reduces the impact of electromagnetic interference, improving signal integrity. This is particularly important for high-frequency applications or sensitive circuits that are more sensitive to electromagnetic interference.

Considering manufacturing tolerances: During the PCB manufacturing process, there may be manufacturing tolerances in the edge area, such as uneven edge cutting or edge residue. When panelizing, it is necessary to avoid V-cuts and stamp holes. Keeping traces and drill holes away from the edges helps to avoid potential manufacturing issues that could affect circuit functionality and reliability.

In summary, keeping traces and drill holes away from the edges of a PCB helps to reduce edge damage, improve reliability, minimize electromagnetic interference, and consider manufacturing tolerances. This is done to ensure the performance and reliability of the PCB and enhance its adaptability to various environments and applications.