As electronic products become increasingly complex and consume more power, the heat generated by the system is also increasing, while the integration density of PCBs is rising. According to relevant data, the area of PCBs has shrunk by half, while the number of integrated components has increased by 3.5 times, resulting in a 7-fold increase in overall PCB integration density.

　　What are the requirements for via size in PCB manufacturing?

　　PCBs and systems are developing towards higher density, faster speeds, and greater heat generation. Furthermore, the problems caused by overheating of circuit boards are receiving increasing attention, making thermal simulation an indispensable step in electronic PCB design. Traditional thermal simulation testing mainly focuses on the selection of via size in PCB manufacturing. Generally, the ratio of outer diameter (R) to inner diameter (r) is >= 8mil (0.2mm).

　　A general recommendation is an outer diameter of 1mm and an inner diameter of 0.3-0.5mm. For denser circuits, an outer diameter of 0.6mm and an inner diameter of 0.4-0.2mm are recommended.

　　For high-current circuits, the outer diameter can be larger, and the via size can be smaller. PCB manufacturers generally recommend using a 0.5mm inner diameter drill bit because it's less prone to breakage. Drill bits smaller than 0.5mm are more likely to break.

　　However, with the trend towards lighter, thinner, shorter, and smaller electronic products, many manufacturers are compressing design parameters to reduce board size. This results in insufficient space for 0.3mm vias, forcing the design of holes around 0.15-0.25mm. These holes are more difficult to manufacture, and should be avoided unless absolutely necessary.

　　Generally speaking, a 0.3mm diameter via is sufficient for most factories' production requirements. If the diameter is smaller than 0.3mm, many factories cannot produce it due to equipment limitations. Even if some factories can produce it, the scrap rate is high, increasing costs.