Wave soldering and tinning is a common problem in the production of electronic product plug-ins. It is mainly because there are many reasons for wave soldering and tinning. If you want to solve the defects of wave soldering and tinning, you must find out the cause of wave soldering and tinning before proceeding. deal with. Next, Guangshengde Technology will share the reasons and solutions.

Wave soldering production line

Reasons for wave soldering:

1. The flux preheating temperature is too high or too low, generally between 100 and 110 degrees. If the preheating is too low, the flux activity is not high. If the preheating is too high, the flux of the incoming tin steel is gone, and it is easy to connect tin;

2. No flux is used or the flux is insufficient or uneven, and the surface tension of the tin in the molten state is not released, which makes it easy to connect to the tin;

3. Check the temperature of the tin furnace, and control it to about 265 degrees. It is best to use a thermometer to measure the temperature of the peak when the peak is raised, because the temperature sensor of the equipment may be at the bottom of the furnace or other locations. Insufficient preheating temperature will cause the component to fail to reach the temperature. During the soldering process, due to the large amount of heat absorbed by the component, it will lead to poor tin drag and form continuous tin; it may also be the temperature of the tin furnace is low or the welding speed is too fast;

4. Regularly check and analyze the tin composition. It is possible that the content of copper or other metals exceeds the standard, which will reduce the fluidity of tin, which is likely to cause continuous tin;

5. Check the orbital angle of wave soldering, 7 degrees is the best, too flat and easy to hang tin;

6. Poor design of IC and power strips, put them together, the IC pin spacing on all sides is <0.4mm, and there is no inclined angle to enter the board;

7. The pcb sinks and deforms during heating, causing continuous tin;

8. The tin steel is too high, the original part eats too much tin, and it is too thick, and it must be connected;

9. There is no solder resist dam between the circuit board pads, and they are connected after printing solder paste; or the circuit board itself is designed with a solder resist dam/bridge, but part or all of it is dropped when it is made into a finished product, so it is easy to connect tin.

The processing method of wave soldering and tin:

1. The flux is not enough or not uniform enough, increase the flow rate;

2. Lianxi speeds up the speed and enlarges the orbit angle;

3. Don't use 1 wave, use 2 wave single wave, the height of the tin does not have to be 1/2, it is enough to just touch the bottom of the board. If you have a pallet, then the tin surface should be on the highest side of the pallet hollowed out;

4. Whether the board is deformed;

5. If 2 waves of singles are not good, just use 1 wave to punch, and 2 waves to hit the pins low, so that the shape of the solder joints can be repaired, and it will be fine.

6. When dealing with wave soldering and tinning, other reasons should be found out: the height of the wave crest distance; whether the chain speed is appropriate; whether the temperature of the tin furnace is appropriate; whether the amount of tin in the tin furnace is sufficient; whether the tin output from the wave crest is even and so on. Find out the reason before proceeding. Troubleshoot.