Requirements for manual soldering on the temperature of electric soldering iron
welding process
1 Warm up and prepare
Before the soldering work, it is necessary to preheat the electric soldering iron to facilitate the smooth progress of the subsequent steps. At the same time, use flux to remove the oxides on the tip of the soldering iron, so that the tip of the soldering iron can reach the cleanest state, and then tinned. The temperature of the soldering iron tip can be transmitted more quickly, and the best welding effect can be achieved. Then hold the welding wire in your left hand, keep the soldering iron steady with your right hand, and start preparations.
2 Heating the weldment
Put the tip of the soldering iron against the junction of the two parts to be welded (the connection between the pad and the lead wire of the component), and the welded part will be heated.
3 Feed tin wire
When the welding surface of the welded piece is heated to a certain temperature, the solder wire contacts the welded piece from the opposite side of the soldering iron. Note: Do not send solder wire to the tip of the soldering iron!
4 Remove the wire
When a certain amount of solder is melted at the connection, immediately remove the tin wire in an upward 45° direction.
(5) Remove the soldering iron
After the solder infiltrates the welding pad and the soldering part of the weldment, upward
Move the soldering iron away at 45°.
2 Formation process of solder joints
(1) When the object to be welded and the solder wire are heated to the melting point of the rosin, which is 172°C to 173°C, the abietic acid in the rosin begins to remove the surface oxide of the object to be welded, and at the same time reduces the surface tension of the object to be welded, providing for the formation of solder joints. Heat conduction and improve solder fluidity.
(2) As the temperature continues to rise, the solder wire begins to melt, and under the action of the flux, the melted solder diffuses along the fine bumps and crystal gaps on the surface of the object to be soldered, and adheres to the object to be soldered Surface, so that the metal atoms between the solder and the object to be soldered are close to each other.
(3) When the temperature rises further, the activity of the metal atoms intensifies, so that the metal atoms between the solder and the object to be soldered diffuse each other, enter the lattice lattice of the other party, and form a metal compound between the solder and the object to be soldered, and Called the alloy layer.
(4) When the temperature is less than 300 ℃, the rosin has not decomposed with charcoal
Before melting, the heat source should be removed, and the solder joint should be cooled naturally to form solder joints.
3 Factors affecting welding
According to the above (1) and (2), the factors affecting welding include the operator, the object to be welded, solder wire, flux and electric soldering iron, etc., and their respective functions are as follows.
(1) Operator: Control the welding time, the master of welding.
(2) The object to be welded: the object to be welded, which provides a carrier for welding, and is related to its own weldability and heat capacity.
(3) Solder wire: The medium that connects the objects to be soldered is related to its own melting point.
(4) Flux: mostly rosin, which removes oxides on the surface of the soldered object and reduces the surface tension of the soldered object.
(5) Soldering iron: Provide heat source for welding.
Among them, solder wire and flux are composites with stable properties, except for the size selection of solder wire when used, it has little influence on welding. The temperature of the electric soldering iron is mainly selected according to the melting point of the solder wire and the heat capacity of the object to be soldered.
