What is soldering technique needed to ensure good connection between conductors on the PCB? Soldering, in layman terms, is merely gluing things together with melted metal. It is the process of amalgamating metals to provide a good electrical connection. It is not difficult, though it does take a little practice to get the hang of it. Having the right tool for the job is also very important.
The basic technique is using a soldering iron and a solder. The soldering iron, is simply a tool that supplies enough heat to melt the solder. Soldering iron comes either with variable temperature or no temperature control.
Solder is an alloy of two metals, with a relatively low melting point, that will flow onto the surface of other metals creating a low-resistance electrical connection. It is generally tin and lead and is usually identified by its tin/lead composition.
If you look at a solder roll, you will usually find numbers like 40/60, 50/50, or 60/40. These are ratios of tin/lead, as percentages. Solder with a higher tin content melts at a lower temperature.
Start off by ensuring that all parts you are connecting are clean from dirt and grease. Also ensure that the mechanical connection are secure before you apply solder, and the parts should not be able to move in relation to each other.
Another important point to note is that both parts of the joint to be made must be at the same temperature.
To actually solder a joint, first apply heat by applying the top of the soldering iron against the things you are joining, immediately apply solder to the point where the iron is contacting. Remember, you should be heating the joints, not the solder!
Feed solder only until there is enough to fill the gap and leave a slight swell. Don't apply too much solder, as it can flow over into other places and cause a short circuit. Remove the solder and the iron smoothly. The whole process should only take two or three seconds at most. Avoid touching the join until it is cooled.
A good solder joint will look shiny and smooth while a bad solder joint will look dull and crinkly.
Should you need to redo a solder joint, always start from scratch. Remove the solder you just put on, and clean the surface before you start the process again.