In the PCBA processing process, in addition to batch soldering using reflow oven and wave soldering machine, manual soldering is also required to produce the product in its entirety.
Matters needing attention when performing manual PCBA soldering:
1. Must operate with electrostatic ring, the human body can generate more than 10,000 volts of static electricity, and the IC will be damaged when the voltage is more than 300 volts, so the human body needs to discharge static electricity through the ground.
2. Wear gloves or finger cover to operate, bare hands can not directly touch the board and components gold finger.
3. Weld at the correct temperature, welding angle, and welding sequence, and keep the proper welding time.
4. Hold the PCB correctly: Hold the edge of the PCB when picking up the PCB and do not touch the components on the board with your hands.
5. Try to use low-temperature welding: high-temperature welding will accelerate the oxidation of the soldering iron tip, reducing the life of the iron tip. If the soldering iron tip temperature exceeds 470 ℃. Its oxidation rate is twice as fast as 380 ℃.
6. Do not apply too much pressure when soldering: when soldering, please do not apply too much pressure, otherwise it will make the soldering iron head damage, deformation. As long as the tip of the soldering iron can fully contact the solder joint, the heat can be transferred. (According to the size of the solder joint to choose a different iron tip, so that the iron tip can also make better heat transfer).
7. soldering shall not knock or shake the iron nozzle: knock or shake the iron nozzle will make the heating core damage and tin beads splash, shorten the service life of the heating core, tin beads if splashed on the PCBA may form a short circuit, causing poor electrical performance.
8. use wet water sponge to remove the soldering iron head oxide and excess tin slag. Cleaning sponge water content to appropriate, water content more than not only can not completely remove the soldering iron head on the solder shavings, but also because of the sharp drop in the temperature of the soldering iron head (this thermal shock to the iron head and the heating element inside the iron, damage is great) and produce leakage, false soldering and other poor soldering, soldering iron head water stick to the circuit board will also cause corrosion of the circuit board and short circuit and other bad, if the water is too little or not wet water treatment, it Will make the soldering iron head damage, oxidation and lead to not on the tin, the same easy to cause false soldering and other poor soldering. Always check the water content in the sponge appropriate, while at least 3 times a day to clean the sponge in the dross and other debris.
9. The amount of tin and flux should be appropriate when soldering. Too much solder, easy to cause even tin or cover up welding defects, too little solder, not only low mechanical strength, and due to surface oxidation layer gradually deepened over time, easy to lead to failure of the solder joint. Too much flux will pollute and corrode the PCBA, which may lead to leakage and other electrical defects, too little does not work.
10. often keep the soldering iron head on the tin: this can reduce the chance of oxidation of the soldering iron head, so that the iron head more durable.
11. solder spatter, the incidence of solder balls and soldering operations are skilled and soldering iron head temperature; soldering flux spatter problem: when the soldering iron directly melted solder wire, flux will rapidly heat up and spatter, when soldering, take the solder wire does not directly contact the iron method, can reduce the flux spatter.
12. When soldering, be careful not to make the soldering iron hot around the plastic insulation layer of the wire and the surface of the components, especially when soldering a more compact structure, the shape of the more complex products.
13. When soldering, it is necessary to self-test.
a. Whether there is leakage of welding.
b. Whether the solder joint is smooth and full, glossy.
c. Whether there is residual solder around the solder joint.
d. Whether there is even tin.
e. Whether the pad is off.
f. Whether the solder joint has cracks.
g. Whether the solder joints have pulled the tip of the phenomenon.
14. Welding, but also need to pay attention to some safety matters, wear a mask, and with a fan and other ventilation equipment to maintain the ventilation of the welding station.
In the PCBA manual welding, pay attention to some basic precautions, can greatly improve the welding technology and product welding quality.
Post time: Mar-03-2022