The composition of solder paste is one of the problems determining the quality of PCB circuit board. The cost of solder paste is mainly composed of metal alloy particles (solder powder), flux, activator and viscosity active agent.
50-60% of the solder paste of alloy particles (solder powder) station is the main component of solder paste, and the purpose of solder paste is to be used for circuit board soldering.
The resin in the solder paste imparts adhesion and prevents reoxidation.
In the solder paste, the active agent mainly removes oxides on the metal surface, which is more in line with the pad surface of the circuit board.
The action of the solvent is due to the fluidity of the rosin, the viscosity is adjusted, and the adhesion is imparted.
The viscosity active agent is for preventing the separation of the solder paste, improving the printability, and preventing the solder paste from collapsing.
At normal temperature, the solder paste can initially bond the electronic components to a selected position. When heated to a certain temperature, the soldered components and pads are connected with the evaporation of the solvent and some additives and the melting of the alloy. Together, they form a permanently connected solder joint after cooling.