What Are the Frequent Failures of Pcb Boards?

In the design and production process of PCB boards, PCB board manufacturers and engineers not only need to prevent PCB boards in the manufacturing and processing of accidents, but also need to avoid the problem of design errors. Here follow TOPFAST to understand it!

Problem 1: PCB board short circuit

This problem is one of the common failures that can directly cause the PCB board can not work, and there are many reasons for this problem, the following we analyze one by one.

◆The biggest cause of PCB short circuit, is the improper design of the solder pad, at this time you can change the round solder pad to oval, increase the distance between the point and the point to prevent short circuit.

◆The improper design of the PCB parts direction will likewise cause the board to short-circuit and not work. Such as SOIC feet if parallel to the tin wave, it will be easy to cause short-circuit accident, at this time you can properly modify the direction of the parts, so that it is perpendicular to the tin wave.

◆There is also a possibility that will also cause a short-circuit PCB failure, that is, automatic plug-in bent feet. As the IPC stipulates that the length of the line foot in 2mm or less and worry about bending the foot angle is too large when the parts will fall, so it is easy to cause a short circuit, you need to leave the solder joint from the line more than 2mm.

In addition to the three reasons mentioned above, there are some reasons that can also lead to short-circuit PCB board failure, such as substrate holes are too large, the temperature of the solder furnace is too low, poor board solderability, solder resist film failure, board contamination, etc., are more common causes of failure, engineers can compare the above reasons and the occurrence of failure one by one to eliminate and check.

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Problem 2: The PCB board appears dark and grainy joints

◆PCB board appears dark or small grain-shaped joints, mostly due to the pollution of solder and dissolved tin mixed with too much oxide, forming a solder joint structure is too brittle. Be careful not to confuse it with the dark color caused by using solder with low tin content.

Another reason for this problem is that the composition of the solder used in the manufacturing process has changed and the content of impurities is too much, so it is necessary to add pure tin or replace the solder. The physical change of the fiber accumulation layer from the glass of the spot, such as the phenomenon of separation between the layer and the layer. But this situation is not a bad solder joint. The reason is that the substrate is overheated, need to reduce the preheating and soldering temperature or increase the substrate travel speed.

Problem 3: PCB solder joints become golden yellow

In general, the PCB solder is presented in silver gray, but occasionally there are golden yellow solder joints appear. The main reason for this problem is the temperature is too high, at this time, you just need to adjust the temperature of the tin furnace can be lowered.

Problem 4: The bad board is also affected by the environment

◆Due to the construction of the PCB itself, when in an unfavorable environment, it is easy to cause damage to the PCB board. Extreme temperature or temperature variation, excessive humidity, high-intensity vibration and other conditions are factors that lead to reduced performance of the board or even scrap. For example, changes in ambient temperature can cause deformation of the board. Therefore, it will destroy the solder joints, bend the board shape, or will also possibly cause the copper traces on the board to break.

◆On the other hand, moisture in the air can cause oxidation, corrosion and rust on metal surfaces, such as exposed copper traces, solder joints, pads and component leads. The accumulation of dirt, dust or debris on the surface of components and boards can also reduce the air flow and cooling of components, leading to PCB overheating and performance degradation. Vibration, dropping, hitting, or bending the PCB can distort it and cause cracks in attendance, while high currents or overvoltages can cause the PCB to be broken or lead to rapid aging of components and pathways.

About the PCB board may appear common failures are introduced here. TOPFAST is a professional and reliable one-stop PCB solution provider for customers who specialize in manufacturing rapid turn prototypes and small quantities. TOPFAST strives to overcome every difficulty in PCB board manufacturing to avoid similar failures and is committed to providing customers with high-quality electronic component products, thus winning wide acclaim in the market.