Essentials of Welding Tools and Welding Methods in Manual Welding Technology
Manual Welding Tools and Welding Methods
Electronic manual welding technology as a widely used welding method, its purpose is to realize the circuit connection, is the wire, electronic components, printed circuit boards printed copper foil alignment, etc. through the solder, flux, in the welding tool high temperature heating connected to a whole, that is, to realize the function of the circuit of the welding technology.
General mass production of circuit boards and components connected to special welding equipment, such as reflow soldering, wave soldering, etc., but there are also a small number of components must be connected manually, a small number of production in the return to repair and other aspects of the link still need to be manual link, so it is very important to master the significance of manual welding technology. In the electronic circuit assembly process, welding technology is an important link.
The installation of radio components, the main use of tin soldering, which not only fixes the parts, but also ensures a reliable current path, the quality of welding, will directly affect the quality of the radio.
1, welding tools (welding equipment)
Soldering iron is brazing one of the main welding tools, divided into endothermic and exothermic, in addition to temperature adjustable. According to the object of welding, solder, flux can choose different power soldering iron welding equipment, soldering iron for electronic welding is generally 20W - 45W.
Commonly used solder for the solder, generally a tin-lead alloy, with good mobility and oxidation resistance. Solder wire is generally made into a tube, a tube filled with rosin, soldering can be used directly; one is no rosin, soldering to add flux. The export of electronic products need to use lead-free solder, mostly Sn-Zn or Sn-Ag-Cu system. Usually use rosin and rosin alcohol solution, the latter soldering effect is good.
Another solder is solder paste, is an acidic solder, corrosive effect on the metal, generally not used.
2, welding method
Generally use the diameter of 1.2-1.5mm of solder wire, soldering with the left hand to take the solder wire, the right hand to take the soldering iron welding method for welding. In the soldering iron in contact with the soldering point at the same time to send the solder, the amount of solder to the right amount. Too much is easy to cause lap welding short circuit, too little components and not solid. Soldering iron head placed on the soldered part that is put into the solder wire. Solder in the welding surface when the solder spread to reach the expected range immediately after the removal of the solder wire and remove the soldering iron.
Soldering operation, the soldering iron temperature is too low, the soldering iron and soldering point contact time is too short, the heat supply is insufficient, the soldering point of tin surface is not smooth, the crystallization of coarse and brittle, like tofu dregs, that is not solid, the formation of false soldering and false soldering. Conversely, if the time is too long (generally no more than 3 seconds), the temperature is too high, the solder is easy to dissipate, so that the amount of solder tin is not enough, it is also easy not to be firm, there may also be bad electronic components and printed circuit boards.
In short, the amount of solder should be moderate, that is, the foot of the part of the soldering point is fully submerged, and its outline is faintly visible. Soldering can not be soldering iron head in the soldering point to move back and forth or force under pressure, in order to weld fast weld good, should increase the soldering iron and soldering point of contact surface. Increase the heat transfer area, welding is also fast. Welding should pay attention to the continuous summary, grasp the heating time, how much tin delivery, not in a point of heating for a longer period of time, otherwise it will make the printed circuit of the pad hot.
3, welding defects
After welding, remove the soldering iron, the solder will not immediately solidify, should stop for a moment and so the solder solidified, after the solidification of the solder, Qi soldering point at the cut excess pins, so that each soldering point smooth and rounded. If not solidified before moving the weldment, the solder will be condensed into sand, resulting in adhesion is not solid and cause false welding.
