Copper solder paste manufacturer-Selection of flux activity.

Flux is one of the main components of solder paste. Solder paste can utilize three types of flux: R flux (rosin flux), RMA flux (mildly activated rosin flux), and RA flux (fully activated rosin flux). The activators in mildly activated and fully activated rosin flux can remove oxides and other surface contaminants from metal surfaces, allowing the melted flux to penetrate into the pads and component leads on the surface mount. The copper solder paste manufacturer advises selecting based on the cleanliness of the surface mount printed circuit board and the freshness of the components, generally opting for moderate activity, with high activity or no activity levels chosen when necessary, including super active levels.

Selection of viscosity.

The viscosity of solder paste is selected based on the application method, and it depends on the characteristics of the application technology (screen mesh aperture, squeegee speed, etc.). The copper solder paste manufacturer informs that for screen printing, a viscosity typically chosen is 100~30000 pa; for stencil printing, high viscosity should be selected, while for injection dispensing with a range of 200~600 pa, a viscosity of 100~200 pa is appropriate.

Selection of metal content.

The metal content in solder paste determines the size of the solder joint. The solder joint increases with the percentage of metal, but as the metal content increases at a given viscosity, slight changes in metal content can significantly affect the quality of the solder joint. For example, for the same thickness of solder paste, if the metal content changes by 10%, it can lead to insufficient solder joints.Copper solder paste manufacturerGenerally speaking, for solder paste used for surface mount components, a metal content of 88%~90% should be selected.

Selection of solder particle size.

The shape of solder particles determines the oxygen content in the powder and the printability of the solder paste. The copper solder paste manufacturer informs that spherical powder is superior to oval powder; smaller spheres have lower oxidation capability.