In the process of wave soldering, tin bars will produce tin dross, but sometimes too much tin dross is found. At this time, we should pay attention to whether there is any problem.
First of all, we should distinguish whether the tin slag that appears is normal tin slag. Generally, the tin slag in the form of black powder is normal, while the tin slag in the form of tofu slag is abnormal. In view of this situation, we analyze the reasons for the following points:
1. In this case, the main reason is because of the problem of the wave furnace of the wave soldering equipment. At present, the design of many wave furnaces is not ideal. The wave peak is very high, the distance between the peaks is too wide, and the distance between the double wave furnaces is too close. There are also rotary pumps used in the equipment, which are all possible causes of tin dross. If the wave peak is too high, the deviation of the temperature reduction may become larger during the process of the solder falling from the peak to the peak, and the solder will be mixed with air, causing oxidation or semi-dissolving of the solder, resulting in the generation of tin dross. If the preventive measures of the rotary pump are not done well, the tin slag will be continuously pressed into the furnace, and the chain reaction of the loop will aggravate the generation of the problem tin slag.
2. The temperature is too low, and the temperature control of wave soldering is relatively low, generally 280 °C ± 5 °C, and this temperature is the minimum temperature required in the solder melting process, and the temperature is lower than the tin can not achieve good melting , indirectly causing excessive tin dross.
3. Missed the most suitable tinning time. In the wave soldering process, the time of adding tin strips is also very critical. The most suitable time is to always keep the distance between the tin surface and the peak as short as possible.
4. The tin slag in the furnace is not cleaned in time, and whether the tin slag is regularly cleaned is also one of the reasons for the problem. Too much tin slag in the furnace will cause the solder falling from the peak to not fall into the furnace as soon as possible, but Staying on the dross leads to uneven heating, thus causing excessive dross.
5. Is there a regular cleaning of the wave furnace? If the wave furnace is not cleaned for a long time, the impurity content in the furnace will be high, which will also lead to excessive tin slag.