How to Avoid Defective Solder Joints in soldering iron Work

How to Avoid Defective Solder Joints in Soldering iron Work

Qualified solder joints are required to be firmly welded, good contacted, shiny, smooth and burr-free solder dots, and the solder should be firmly integrated with the welded components. There should be no phenomena such as cold soldering and false soldering. The Defective solder joints include bridging, excessive solder, solder spikes, floating solder, voids, excessive rosin, bubbles, insufficient solder, copper foil warping, etc.

How to repair of defective solder joints?
During the welding process of electronic products, we often get defective solder joints. In this case, it is necessary to repair the unqualified solder joints. Usually,we don't add solder to solder the joint once more. First ,the solder of the unqualified solder joints should be completely removed, then the components can be re-welded.It is better to supple solder wire with rosin core while repairing .

How to Avoid Defective Solder Joints?

1. Choose different types of soldering irons according to the welding tasks.

2. The posture of welding should be correct.

3. Pay attention to the pre-welding treatment step. Clean and remove oxides from components and solder wires before welding.

4. Keep the soldering iron tip clean during welding

5. Control the welding temperature and time.There should be sufficient heat and temperature during the soldering. If the working temperature is too low, the solder's fluidity is poor and it is easy to solidify, resulting in cold soldering. If the temperature is too high, the solder will flow, and it will be difficult for the solder joints to hold the solder. The decomposition speed of the flux will be accelerated, which will accelerate the oxidation of the metal surface and the solder pads on the printed circuit board will fall off. Especially when we are using natural rosin flux, the over high soldering temperature may cause oxidation, peeling and carbonization, resulting in cold soldering. Moreover, excessive temperature may also damage the components. The welding time must be appropriate, neither too long nor too short,it is better to control the welding time as short as possible .

6. Amount of solder.

7. Do not apply force to the components and solder pads with the soldering iron tip. During the welding process, some people apply force to components and solder pads with the soldering iron tip to increase the heat transfer speed. In fact, the heat transfer speed of the soldering iron tip is mainly achieved by increasing the contact area between the soldering iron tip and the welded parts. Applying force to the solder joints will not effect but bring some hazards and damage to components and solder pads.

8. Direction of removing the soldering iron tip. It is necessary to choose the appropriate removal direction according to the specific welding situation.

9. Fix the welded parts. Do not move or touch the welded parts before the melted solder solidifies. Especially when soldering the SMD, we have to remove the tweezers after the solder has solidified properly,or it will cause the displacement of the welded parts and defective solder joints.

10. Pay attention to safety during the soldering process and avoid burning and electric shock.

11.The soldering iron tip should be put on the soldering stand after the soldering tasks.

12. Prepare several soldering irons with different powers for different work occasions.