As PCB manufacturer China knows that，regarding PCB assembly, lead-free solder paste is the preferred choice because it does not cause oxidation or deterioration. Lead-free solder paste consists of tin, silver, copper, and copper alloy. However, solder paste’s composition differs depending on the components used in PCB assembly. As PCB manufacturer knows that, for this reason, it is crucial to choose the correct paste for the specific application.

You should control the temperature of the solder paste so that it does not overheat the components. Some solder paste manufacturers allow a little increase in the temperature during activation. A flat temperature curve is desirable for solder ability and a longer processing window. The temperature of the active zone should be relatively constant, which is essential for FPC SMT assembly. However, some furnaces cannot maintain the solder paste temperature evenly.

The formulation of FPC SMT solder paste does not contain special requirements for the composition of the solder paste. However, the solder paste should have excellent printing properties. It should be easy to print and release, and it should be able to adhere firmly to the pads of the flexible PCB. Also, it should not cause the mold to collapse after printing or clog the steel mesh. Furthermore, it should be suitable for medium and high-speed placement machines.

As the solder paste consists of metals, it is susceptible to oxidation. This reduces the solder balls’ quality and defeats soldering’s purpose. Therefore, it is essential to store solder paste in an air-tight container and store it at a low temperature. Heat is harmful to the metals in solder paste and oxidizes the flux that holds the solder powder together.