1, function: weld components and wires to make them reliably connected, with good electrical conductivity and certain mechanical strength, and decompose original weldments.
2, welding basic essentials:
(1) Clean the metal surface to ensure good welding.
(2) When heating, reach the optimal welding temperature.
(3) have a certain welding time (welding speed should be appropriate).
(4) Solder should have good wetting ability in liquid state (with the help of flux).
3. Solder joint quality requirements: good electrical contact; Good mechanical properties; It's beautiful. Strictly prevent virtual welding and repair welding. The solder joint should not be too big, it should be shiny and beautiful, but the firmness is the first.
Note: Welding technology is not only related to the labor productivity and production cost of the whole machine assembly, but also the key to the quality of electronic products. To make each solder joint not only uniform and beautiful, but also have good electrical properties and mechanical strength, it is not something that can be mastered overnight. A person engaged in electronic technology, especially a beginner, must seriously study the theoretical knowledge about welding, master the essentials of welding technology and be skilled in welding operation, so as to ensure welding quality and improve work efficiency.
4. Basic welding steps:
Hold an electric soldering iron in your right hand. The left hand grips the component or wire with needle-nosed pliers or tweezers. Before welding, the electric soldering iron should be fully preheated. The surface of the welding head blade should eat tin, that is, a certain amount of solder should be coated.
(2) cling the surface of the welding head blade to the welding spot, and heat the welding surface to the temperature where the solder melts. The electric soldering iron forms an angle of about 60℃ with the horizontal plane, so that molten tin flows from the welding head to the welding point, and the solder melts and fills the surface of the welded metal. The welding head stays at the welding spot for 2-3 seconds.
(3) When the solder on the solder joint and the flow toughness are suitable, lift the welding head. The left hand still holds the part. Only after the tin at the solder joint cools and solidifies can the left hand be released.
④ Turn the wire with tweezers to ensure that it is not loose, and then cut off the excess wire with side cutters.
5, the basic technical requirements of welding quality
(1) The solder joint shall be firm and have certain strength;
(2) There should be no virtual welding, false welding and missing welding;
③ There should be no lap welding, touch welding, bridging and tin splashing between solder joints;
(4) There should be no burr, notch, trachoma and air hole in the solder joint;
⑤ Solder joints should be bright and uniform in size;
⑥ The surface of solder joint should be clean and tidy without flux residue;
⑦ The solder on the solder joint should be adapted;
⑧ Master the welding temperature to avoid scalding wires and components.