Tips for soldering iron wire and welding essentials
Welding essentials
(1) The contact method between the soldering iron tip and the two welded parts (as shown in Figure 6)
Contact position: The soldering iron tip should simultaneously contact the two connected components (such as solder pins and pads). The soldering iron is generally tilted at a 45 degree angle and should avoid contacting only one of the components. When the thermal capacity of two welded parts is significantly different, the inclination angle of the soldering iron should be adjusted appropriately. The smaller the inclination angle between the soldering iron and the welding surface, the larger the contact area between the welded part with a larger thermal capacity and the soldering iron, and the stronger the thermal conductivity. The tilt angle for LCD soldering is around 30 degrees, while the tilt angle for soldering microphones, motors, speakers, etc. can be around 40 degrees. Two welded components that can reach the same temperature in the same time are considered to be in an ideal heating state.
Contact pressure: When the soldering iron tip comes into contact with the workpiece, a slight pressure should be applied. The strength of heat conduction is proportional to the magnitude of the applied pressure, but the principle is to not cause damage to the surface of the workpiece.
(2) Method of supplying welding wire
The supply of welding wire should master three essentials, namely supply time, location, and quantity.
Supply time: In principle, when the temperature of the workpiece reaches the melting temperature of the solder, the solder wire is immediately sent.
Supply location: It should be between the soldering iron and the workpiece, and as close as possible to the solder pad.
Supply quantity: It should depend on the size of the workpiece and the solder pad. After covering the solder pad with solder, the solder should be higher than one-third of the diameter of the solder pad.
(3) Welding time and temperature settings
A. The temperature is determined by actual use, and it is most suitable to solder a solder dot for 4 seconds, with a maximum of 8 seconds. When the soldering iron tip turns purple, the temperature is set too high.
B. Generally, for direct insertion of electronic materials, the actual temperature of the soldering iron tip is set to (350~370 degrees); Surface mount material (SMC) material, set the actual temperature of the soldering iron tip to (330~350 degrees)
C. Special materials require special setting of soldering iron temperature. FPC, LCD connectors, etc. require silver tin wire, and the temperature is generally between 290 ° C and 310 ° C.
D. When soldering large component pins, the temperature should not exceed 380 degrees, but the power of the soldering iron can be increased.
(4) Welding precautions
A. Before welding, observe whether each welding point (copper sheet) is smooth, oxidized, etc.
B. When welding items, it is important to focus on the welding points to avoid short circuits caused by poor soldering of the circuit
4. Check after operation:
(1) After using the soldering iron, the remaining tin on the tip should be wiped clean with a sponge.
(2) After work every day, it is necessary to clean the solder beads, solder slag, dust and other objects on the soldering iron holder, and then place the soldering iron on the soldering iron holder.
(3) Place the cleaned soldering iron in the upper right corner of the workbench.
