Sweat-bonding PCB, Copper-coin

Sweat bonding is the process of bonding PCB and metal heat sink by soldering process. The solder selected must have high melting point and lead-free characteristics so that the solder does not melt during assembly. Rocket PCB builds millions of PCBs that are bonded by sweat soldering. They are used in mobile base stations with good quality and reliability.
We have extensive experience in solder paste selection and void control. Compared with other bonding materials, sweat bonding has the following advantages.

Low cost: Even special high temperature solders are more expensive than standard lead-free solder pastes. It is cheaper than other bonding materials. For an adhesive film such as CF-3350, some material is wasted based on the bonded area. The solder paste is stenciled to the joint area, almost no waste is wasted. In addition, soldering is also a comparable low cost process.

Excellent performance: As a pure metal material, its conductivity is very good for RF application. The bond strength is also stronger than resin based adhesives or prepreg.

Due to its limitation, sweat bonding process is not frequently used in high power PA PCB.

1. As some flux will remain in the welding area, which will lead to voids, the electrical performance of PCB may be affected in the RF area.
2. The solder paste melting point is lower than the component soldering temperature, may be re-melted