PCB Design Improves Soldering Reliability

The most important and difficult to control point in electronic assembly is the reliability of soldering. Soldering is a special process, and its results cannot be verified by subsequent monitoring or measurement, and its quality problems will only appear after the product is delivered. reliability.

For example, when designing the PCB pads, in order to ensure the balance of the surface tension of the molten solder, the pads at both ends of the SMD should be symmetrical; the remaining dimensions of the component soldering ends or the pins and the pads should be able to ensure that the solder joints can form a meniscus ;In order to increase the welding qualification rate of fine-pitch pin package components, the design of the process guide plate can be used; in order to improve the welding qualification rate of the pads connected to the large-area copper foil, the "fancy" pad design can be used, etc. Wait. Correct PCB pad design, if there is a small amount of skew during patch processing, can be corrected due to the surface tension of molten solder during reflow soldering. However, if the PCB pad design is incorrect, even if the placement position is very accurate, welding defects such as component position deviation and suspension bridges are likely to occur after reflow soldering.

In addition, in terms of component package selection, substrate material selection, assembly method, component layout, solder mask design, etc., there are different design requirements to ensure the qualification rate and reliability of welding.

The manufacturable design of PCB requires designers to fully understand all aspects of the manufacturing process and take comprehensive consideration to select the optimal design scheme. For group-type enterprises, the balance and selection of different manufacturing capabilities of each manufacturing plant should also be considered within the scope of comprehensive consideration. This has very high requirements for the comprehensive ability of design engineers. It can even be said that the manufacturable design of PCB should be carried out by a team of different professionals, not just a design engineer.