In the welding of electronic circuit boards, the surface of the tin point after t
in wire welding is rough, bridged, tin beads, board surface is dirty, and the circuit board is short-circuited. The main materials of electronic tin wire are tin wire, tin bar, auxiliary Flux, PCB board surface and electronic components are several parts, so which part has problems will eventually affect the quality of tin wire.
1. The surface of the PCB board is wet: the PCB board has a drying procedure in the process of making the board. When the color of the tin wire appears, it generally has a considerable relationship with the temperature. Due to special circumstances, the humidity of the PCB board surface is too high, and it is easy to cause tin explosion when the tin wire is in contact with the high-temperature tin liquid. When the temperature of the tin wire is too high, the surface of the tin liquid will turn yellow. At this time, it is necessary to adjust the appropriate working temperature for the temperature of the tin furnace. the
2. When the circuit board is soldered and connected to the aging process, it will be found that some circuit boards are short-circuited. In addition to the problems of circuit board design and electronic components, you can find out from the following aspects. The time for eating tin wire on the circuit board is too short , resulting in poor welding. The flux itself is not very active, which weakens the wettability of the tin wire and its expansibility. The direction of the tin entering the circuit board is opposite to the direction of the tin wave, and too much oxide on the liquid surface of the tin wire will affect the soldering. the
3. After tin wire, it is found that the tin spots are dull and dull, and the quality of tin wire has a great relationship with the welding effect. If there are too many impurities in the tin wire, the residue will be suspended on the surface of the tin liquid after the tin wire is melted, and the residue will stick to the PCB surface during soldering. The acid substances corroding the solder joints will also cause the tin joints to be dull and dull. Another aspect is that the degree of tin wire is too low. If the tin wire reaches more than 50% tin, the solder joints will be shiny. The tin wire itself contains a small amount of various metal elements. When the content of these metal elements exceeds its limit, it will affect the surface of the tin point. When tinning, the surface of the tin liquid is required to be free of impurities. When the surface of the tin liquid is oxidized too much, it should be cleaned in time, otherwise it will affect the surface gloss of the tin dots.