Wave soldering even tin causes and treatment methods

Wave soldering machine even tin is a common problem in the production of electronic products plug-in wave soldering, mainly because of the wave soldering even tin caused by a variety of reasons. If you want to adjust the wave soldering to reduce even tin, it is necessary to find out the causes of wave soldering even tin. Here to share the causes and processing ideas.

Wave soldering with tin causes.

1. Flux preheating temperature is too high or too low, generally in 100 ~ 110 degrees, preheating too low, flux activity is not high. Preheat too high, into the tin steel flux has been gone, but also easy to even tin.
2. No flux or flux is not enough or uneven, the surface tension of the molten state of tin is not released, resulting in easy to even tin.
3. Check the temperature of the tin furnace, control at about 265 degrees, it is best to use a thermometer to measure the temperature of the wave crest when the wave crest hit, because the temperature sensor of the equipment may be in the bottom of the furnace or other locations. Preheating temperature is not enough will lead to components can not reach the temperature, the welding process due to the component heat absorption, resulting in poor drag tin, and the formation of even tin. There may also be a low temperature of the tin furnace, or welding speed is too fast.
4. Regular checks to do a tin composition analysis, it is possible that copper or other metal content exceeds the standard, resulting in reduced mobility of tin, easily caused by even tin.
5. Check the angle of the wave soldering track, 7 degrees is best, too flat easy to hang tin.
6. IC and row of bad design, put together, four sides IC dense foot spacing < 0.4mm, no tilt angle into the board.
7. PCB heated middle sink deformation caused by even tin.
8. Tin steel is too high, the original eat too much tin, too thick, must even.
9. The circuit board pads are not designed between the solder dam, connected after printing on the solder paste; or the circuit board itself is designed to have a solder dam / bridge, but in the finished product into a part or all off, then also easy to even tin.

Wave soldering even tin treatment methods.

1. Flux is not enough or is not even enough, increase the flow.
2. United tin to speed up the speed point, the track angle enlargement point.
3. Do not use 1 wave, with 2 waves of a single wave, eat tin height does not have to be 1/2, can just touch the bottom of the board is enough. If you have a tray, then the tin surface in the tray hollowed out the highest surface is good.
4. Whether the board is deformed.
5. If the 2 wave single hit is not good, with 1 wave punch, 2 wave hit low low touch the pins on it, so you can repair the shape of the solder joint, out on the good.