We know that there are many types and specifications of solder paste in SMT chip processing plants. Solder paste is mainly classified according to alloy composition, particle size, viscosity, cleaning method, etc., and the price will naturally vary depending on the category. Therefore, how to choose the right solder paste has a great impact on product quality and cost. Let’s take a look at the following Sanjing:

Under normal circumstances, the selection should be made according to the specific production environment, referring to the activity, viscosity, powder shape, particle size and melting point of the solder paste for chip processing.

1. When selecting solder paste in SMT chip processing, the alloy composition should be determined first. Alloy is the material that forms solder paste. It forms an alloy layer with the metal to be soldered. At the same time, the alloy composition also determines the soldering temperature. The alloy composition is mainly selected according to the electronic product and the process, and the alloy composition that is compatible with the component welding should be selected as much as possible, and the process factors such as the welding temperature should also be considered.

2. After determining the alloy composition in the solder paste, a flux suitable for the production process should be selected, because the flux determines the printability and solderability of the solder paste.

When selecting a flux, its activity should be selected according to the storage time of the printed circuit board and components and the degree of surface oxidation. The activity of flux can be divided into: active (RA), medium active (RMA), inactive (R), water wash (OA), no-clean (NC), etc. The general product is RMA type, and the high reliability product is R type. The printed circuit board and components are stored for a long time, and the surface is severely oxidized. RA type should be used, and it should be cleaned after welding.

3. The alloy composition and flux ratio in the solder paste should be determined, because the alloy composition and flux ratio will directly affect the viscosity and printability of the solder paste. The viscosity of the solder paste should be selected according to the process of applying the solder paste and the assembly density of the SMT patch. There are many ways to apply the solder paste, and different application methods have different requirements for the viscosity of the solder paste.

The above is about how to choose the appropriate SMT patch solder paste content, I hope it can be helpful to everyone!