TitleWhat is the difference between rosin flux solder paste?What is the difference between rosin, soldering flux and solder paste? What are their respective functions? Thank you
Difference and function:Rosin --- solid pine resin, the raw material for making flux.Flux - liquid, main component, isopropyl alcohol, rosin, organic acid, etc., used for welding parts of electronic circuit board, removing oxide on pad, helping solder flow and expansion.Solder paste --- pasty viscous body, mainly consisting of metal powder, rosin, organic acid, thixotropic agent and active agent. Welding for SMT automatic mount technology. It is an upgraded substitute of soldering flux and soldering process. It has high automation and high welding accuracy.
The flux is known, rosin, solder paste to use flux, the most critical is to increase the welding and welding solder objects (poor infiltration effect infiltration, solder is not well attached to the welded object, appeared a round ball, it is easy to weld), other auxiliary heat removal, such as oxidation conduction, reduce surface tension, so that the metal solder joint appearance etc.. Flux is divided into three categories: one is inorganic flux, two is organic flux, and three is rosin. Inorganic flux is generally a certain acid or salt, such as phosphate H3PO4, organic flux is mainly some organic acid or organic halogen; relatively speaking, the most active inorganic flux, remove the oxide film had the best effect, but also has strong corrosion resistance, it is easy to hurt the metal and solder joints, generally can not be used in the welding of electronic products. Solder paste is emulsified with oil after the inorganic flux, welding can be cleaned by solvent, but some parts of the circuit board is difficult to clean, so generally do not recommend the use of solder paste. Organic flux is second only to inorganic flux, and also has certain corrosiveness, and the residue is not easy to be cleaned, and the volatile matter is harmful to human body. Is the main component of rosin rosin acid and Levopimaric acid, generally neutral, liquid has a certain activity, showed weak acidity, can react with the metal oxide surface, formation of abietic acid copper compounds, and suspended in the surface of the solder, and the use of no corrosion, insulation resistance. Rosin is, in general, the best soldering flux.
The effect of flux in general are "auxiliary heat conduction" and "removing the oxide, reduce the surface tension of welding material, welding material removal is surface oil, increase the welding area, prevent oxidation and other aspects, in the aspects of the more critical role is: two" the removal of oxides and reduce the surface tension of the welding material.Strictly speaking, solder paste is used to weld metal pieces of large area, such as shangpozi, tin lead barrel what, in the iron contact moment, solder paste by high temperature contact iron will produce gas, the welded metal surface dirt removed rapidly, so it is easy to "tin", but also harm large, is acidic, corrosive to metal joints around, this is the second. The biggest drawback in the interaction of high temperature and paste will produce water like liquid, the conductivity of many, therefore stronger than water, electric line on joint close is not appropriate.
