Introduction to the basic steps of welding operations
Step 1: Prepare to weld. Hold the welding wire in your left hand and the soldering iron in your right hand to enter the welding preparation state. The soldering iron tip is required to be kept clean, free of oxides such as welding slag, and coated with a layer of solder on the surface.
Step 2: Heating the weldment. Place the soldering iron tip against the connection between the two weldments and heat the entire weldment for about 1 to 2 seconds. When soldering components on printed circuit boards, attention should be paid to making the soldering iron tip contact two objects to be soldered at the same time. Wires and terminals, component leads and pads must be heated evenly at the same time.
Step 3: When the welding surface of the soldering piece fed into the soldering iron is heated to a certain temperature, the solder wire contacts the soldering piece from the opposite side of the soldering iron. Note: Do not feed the solder wire to the soldering iron tip!
Step 4: Remove the welding wire. When the welding wire melts a certain amount, immediately remove the welding wire in the 45° direction to the upper left.
Step 5: After removing the soldering iron and letting the solder soak into the pad and the welding part of the weldment, remove the soldering iron in a 45° direction to the upper right to end the welding. From the beginning of the third step to the end of the fifth step, the time is about 1 to 2 seconds.
Precautions for welding operations
1. Keep the soldering iron tip clean and maintained. When welding, the soldering iron tip is at high temperature for a long time and is easily oxidized and stained with a layer of black impurities. Therefore, be sure to wipe the soldering iron tip with a wet sponge at any time. When it is not used for a long time, tin should be added to the soldering iron tip to prevent the tip from oxidizing and making it impossible to stick tin.
2. When increasing the contact area to speed up heat transfer and heating, all parts of the weldment that require solder infiltration should be heated evenly, rather than just heating a part of the weldment, let alone using a soldering iron to increase pressure on the weldment.
3. Soldering iron evacuation requires timely evacuation of the soldering iron, and the angle and direction during evacuation are related to the formation of solder joints.
4. Do not move the solder until the solder solidifies. Do not move or vibrate the weldment, otherwise it will easily cause the solder joint structure to become loose or weak.
5. The amount of solder should be moderate, and the tin wire should be filled with flux made of rosin and activator.
6. The amount of flux should be moderate. Excessive use of rosin flux will inevitably require erasing the excess flux after welding, prolonging the heating time and reducing work efficiency. When the heating time is insufficient, the defect of "slag inclusion" is easily formed.
7. Do not use the soldering iron tip as a tool to transport solder (soldering with tin). Some people are accustomed to using the soldering iron tip as a tool to transport solder for soldering, which will cause oxidation of the solder.
Because the temperature of the soldering iron tip is generally above 300°C, the flux in the solder wire is prone to decomposition and failure at high temperatures, and the solder is also in an overheated, low-quality state.
