In the PCBA process, in addition to reflow welding and wave soldering, manual welding is also required to complete the production of the product.
Matters needing attention during PCBA manual welding:
1 must be with static ring operation, the human body can produce more than 10000 volts of static electricity, and IC in more than 300 volts of voltage will be damaged, so the human body needs to discharge through the ground wire.
2. Operate with gloves or finger covers. Bare hands shall not directly touch the machine board and components with gold fingers.
3. Conduct welding at the correct welding temperature, welding Angle and welding sequence, and maintain appropriate welding time.
4. Correctly pick up the PCB: When picking up the PCB, hold the edge of the PCB without touching the components on the board.
5. Use low temperature welding as far as possible: High temperature welding will accelerate the oxidation of the soldering tip and reduce the lifetime of the soldering tip. If the tip temperature of the soldering iron exceeds 470℃. It oxidizes twice as fast as 380℃.
6. Do not press too much during welding: Do not press too much during welding, otherwise the tip of the soldering iron will be damaged and deformed. Heat can be transferred as long as the tip of the soldering iron is in full contact with the solder joint. Choose different tips according to the size of the solder joint. This also makes the tips better for heat transfer.
7. Do not tap or swing the soldering iron tip: tapping or swinging the soldering iron tip will damage the heating core and splash the tin bead randomly, shortening the service life of the heating core. If the tin bead splashes on the PCBA, a short circuit may be formed, resulting in poor electrical performance.
8. Use a wet sponge to remove oxide and excess tin. How not only to properly clean sponge water content, water content is not completely remove the soldering iron head crumbs, also because of the welding head temperature fell sharply (this kind of thermal shock on the welding head and the inside of the soldering iron element, damage is very big) and produce the bad welding, such as welding, cold joint leakage water adhere to the PCB soldering iron head can cause circuit board as well as the corrosion and short circuit, if too little water to wet water treatment or not, will make the welding head is damaged, and cause no tin oxide, also easy to cause bad virtual welding such as welding. Often check the water content in the sponge is appropriate, at the same time, at least 3 times a day to clean the tin residue in the sponge and other sundries.
9. The amount of tin and flux for welding should be appropriate. Too much solder, easy to cause tin or cover up welding defects, too little solder, not only the mechanical strength is low, and because the surface oxidation layer gradually deepened over time, easy to lead to solder joint failure. Too much flux will contaminate and corrode PCBA, which may lead to electric leakage and other electrical defects. Too little flux will not work.
10. Often keep tin tip: this can reduce the oxidation chance of the tip, make the tip more durable.
