No-clean flux

During the soldering process, the flux can remove the oxides on the surface of the welded metal, prevent the re-oxidation of the solder and the soldering surface during soldering, reduce the surface tension of the solder, enhance the wettability, and promote the transfer of heat to the soldering area. The performance of the flux directly affects the welding quality. If it is not selected properly, it will not only fail to perform the welding function, but will cause reliability problems such as reduced mechanical strength, electrochemical corrosion, and electromigration. Therefore, the correct choice of flux is very important.

 

 

The flux is usually matched with the solder. It should be based on the solder alloy, according to different process methods, and at the same time according to the soldered component pins, the coating material of the PCB pad, the degree of oxidation of the metal surface, and the electrical performance of the product for cleanliness The specific requirements are selected.

 

 

1. General principles for selecting flux for group soldering processes such as dip soldering and wave soldering

 

 

1. Under normal circumstances, electronic products such as satellites, aircraft instruments, submarine communications, life-protecting medical devices, and weak signal test instruments must use cleaning fluxes for military and life support products.

 

 

2. No-clean or clean-type flux can be used for electronic products such as communications, industrial equipment, office equipment, and computers.

 

 

3. General household appliances and electronic products can use no-clean flux or RMA (medium activity) rosin flux without cleaning.