Role Of Soldering Fluxes In Industrial Applications
You must have seen the electronic circuits to be joined with the solders
. The electricians often work with a special instrument which produces heat from the electric current and this heat is used to melt the soldering wires which are made from the alloys of different metals. The soldering fluxes are the materials which provide the necessary medium for this purpose. A question which naturally arises in the mind is why are these fluxes used and what are their different types?
While joining the two metals or alloys, it is quite natural to expect that there will be some kind of impurity on their surface. This impurity is usually washed through the chemical or water action before the soldering is done. However, this may not be possible all the time to clean it or that it gets cleaned. So, there will be a tendency to oxidize the surface of the metal under the influence of heat. The soldering fluxes are used to prevent the impurities from oxidizing because if that happens, the soldering will not happen effectively. The joints will remain weak.
There are different types of soldering fluxes which are used in the industry that can be conveniently categorized in three forms. One is the rosin based soldering process which makes use of the sap of the pine trees called the rosin for de-oxidation of the residues. Second category is that of the water soluble flux which is made from the organic glycol acid base. Even the inorganic fluxes are available which are generally more powerful that the organic ones. The water soluble fluxes are more powerful than the rosin based ones. The third category of fluxes is called brazing which is a mixture of brass alloy.
The choice of these fluxes is dependent on the nature of metal or alloy surface which has to be worked on and on the purpose which soldering is expected to achieve. While some types of solders might find good applications where there is not much of strength required, some other formulations are used in making strong mechanical joints. Some of the following characteristics of soldering fluxes are modified on the basis of their formulations:
1. Halides are present in some activators which assist in the removal of oxides
due to their quick ionization.
2. The surfaces which are difficult to wet need the fluxes which are of higher activity levels.
3. Some solders are of rapid reflow characteristics. These include the laser based, hot bar and even the induction based heating. These have the capability to heat under the five seconds.
4. Pin transfer or dripping: Some of the soldering material can be kept in the liquid state and the thing which has to be soldered is dipped into it. It creates a thin layer of pin transfer on the metal or alloy surface.
5. Void limits: Soldering creates voids of air and this might not be acceptable in certain key requirements. Soldering fluxes which produce low voids are preferred.