Analyze the causes of solder connection (short circuit) during wave soldering and the solutions

With the continuous development of high-tech products in our country, the process design of circuit boards in mechanical equipment is becoming increasingly complex, and the spacing between lead pins is getting denser and denser, which easily leads to the phenomenon of solder connection after soldering, that is, short circuit. For this reason, how should we analyze the causes of wave soldering and find corresponding solutions? Today, Shenzhen JJYTin bar manufacturerLet's take a look at the causes of solder connection in wave soldering and the solutions:

Soldering, also known as short circuit, is one of the most common defects in wave soldering technology. First of all, when we encounter wave soldering with continuous soldering, we should first check the direction of passing through the board. If the direction of passing through the board is incorrect, it is very easy to cause continuous soldering. Furthermore, we check whether the welding materials are of high quality. Low-quality solder rods will produce a large amount of impurities (that is, tin slag). Excessive impurities can easily cause uneven heating during welding, resulting in unstable welding. Therefore, we try to use tin bars with a higher tin content or higher flux activity. If conditions permit, we can use lead-free tin bars as soldering materials as much as possible. High-quality tin bars have fewer impurities, are more stable during soldering and have better performance.

The above two are the reasons that are relatively easy to identify and solve. Other common reasons for continuous soldering that need to be investigated and analyzed in wave soldering include the following:

1If there is no flux used or the flux is insufficient or uneven, the surface tension of the tin in the molten state has not been released, resulting in easy soldering. You can add a large amount to see.

2There is no solder mask dam designed between the pads of the circuit board, and they are connected after being printed with solder paste. Or the circuit board itself is designed with a solder mask dam/Bridge, but if part or all of it falls off during the finished product process, then it is also easy to attach the tin.

3Check the temperature of the tin furnace and control it at265It's best to measure the temperature of the wave peak when it rises with a thermometer, as the temperature sensor of the equipment may be at the bottom of the furnace or other locations. Insufficient preheating temperature will cause the components to fail to reach the required temperature. During the soldering process, due to the large amount of heat absorbed by the components, poor solder dragging occurs, resulting in solder connection. It could also be that the temperature of the tin furnace is too low or the welding speed is too fast. It is recommended to use before weldingKICTest whether the temperature of the components and the board surface meets the welding requirements;

4If the tin material is too high and the original component is exposed to too much or too thick tin, it will definitely cause tin adhesion.

5Regularly check and conduct a tin composition analysis. It is possible that the content of copper or other metals exceeds the standard, which leads to a decrease in the fluidity of tin and makes it easy to cause tin adhesion.

6The preheating temperature of the flux is either too high or too low, generally within100~110If the preheating is too low, the activity of the flux will not be high. The preheating is too high. Enter the tin steelfluxIt's gone and it's also easy to attach tin.

7Check the track Angle of the wave soldering.7The best temperature is too high. If it's too high, it's easy to get tin attached.

8,pcbThe heat causes the middle to sink and deform, resulting in tinning.

9,ICIt is poorly designed with power strips and placed together on all four sidesICClose pitch between feet<0.4mmThere is no inclination Angle for entering the plate.

The above-mentioned reasons need to be investigated by us on a daily basis and discovered and resolved in a timely manner.

Soldering in wave soldering is a very common problem. Using high-quality solder strips or lead-free solder strips can solve most of these problems. ReducePADWith the ring width and the height of the control pins, the tin pan can effectively reduce the bridging phenomenon. Finally, our daily inspection is the most crucial.

Shenzhen JJY Industrial Technology Co., Ltd. mainly engages in the production and operation of:SMTSolder paste manufacturers of solder paste, syringe solder paste, lead-free solder wire, wave soldering bar, automatic soldering wire, etc.