(1) contact mode between the soldering iron head and the two welded parts

Contact position: the soldering head should contact the two welded parts (such as the soldering feet and the pad) which are connected at the same time.When the thermal capacity of two welded parts is relatively large, the tilt Angle of the soldering iron should be adjusted appropriately. The smaller the inclination Angle of the soldering iron and the welding surface, the larger the thermal capacity of the welded parts and the contact area of the soldering iron will increase, and the thermal conductivity will be strengthened.For example, the inclination Angle of LCD welding is around 30 degrees, while the inclination Angle of microphone, motor and horn can be around 40 degrees.Two welded parts can reach the same temperature at the same time, which is regarded as the heating ideal state.

Contact pressure: slight pressure should be applied when the soldering iron head is in contact with the welded parts.

(2) supply method of welding wire

The supply of welding wire should master 3 essentials, that is, supply time, position and quantity.

Supply time: in principle, the solder is heated up to the solder melting temperature is immediately sent to the solder wire.

Supply position: between the soldering iron and the welded parts and as close as possible to the pad.

Quantity supplied: the size of the weld piece and pad should be determined. Solder can cover the solder pan and the solder can be higher than 1/3 of the diameter of the pad.

(3) setting of welding time and temperature

A. The temperature is determined by actual use. It is most appropriate to weld A tin point for 4 seconds, and the maximum time is no more than 8 seconds.

B. directly insert the electronic material, and set the actual temperature of the iron head (350~370 degrees);Surface mount material (SMC) and set the actual temperature of the soldering iron head (330~350 degrees).

C. for special materials, the temperature of iron shall be set specially.For FPC, LCD connector, etc., use silver-tinted wire, and the temperature is generally between 290 and 310 degrees.

D. for large parts, the temperature should not exceed 380 degrees, but the power of the soldering iron can be increased.

(4) matters needing attention for welding

A. Before welding, observe whether each welding spot (copper sheet) is smooth, clean and oxidized.

B. when welding articles, check the welding spot to avoid short circuit caused by poor welding line