Advantages of Solder Paste in Laser Soldering Applications

Advantages of Solder Paste in Laser Soldering Applications   

Application of Laser Solder Paste in Laser Soldering Machines

 Solder paste is a modern welding material developed alongside Surface Mount Technology (SMT). It is a complex system composed of solder powder, flux, and other additives mixed into a paste-like consistency. At room temperature, solder paste exhibits a certain viscosity, allowing it to temporarily hold electronic components in place. When exposed to soldering temperatures, the solvent and some additives evaporate, permanently bonding the components to the printed circuit board (PCB) pads.

                Laser Solder Paste Welding Process Flow 

 While traditional reflow soldering has been the standard method for SMT assembly—and its contributions to the industry are undeniable—issues like insufficient solder paste and cold solder joints remain common in the process. With the maturation of laser technology, the combination of laser heating and solder paste has effectively addressed these challenges in SMT production. Gradually, laser solder paste welding has gained recognition, and today, an increasing number of manufacturers are adopting laser solder paste systems for their production lines.

So, what are the advantages of laser solder paste welding? And where is it being applied?

              Precision MLCC Laser Solder Paste Welding - Animated Process Demonstration

Advantages of Laser Solder Paste Welding:

Laser soldering is a rapid non-contact welding process with a remarkably short welding time that can achieve 300 milliseconds. This high-speed welding process generates no solvent emissions, produces absolutely no spatter during operation, and yields perfectly formed solder joints completely free of residual solder balls. Laser solder welding is an advanced welding technology that utilizes laser as the heat source to melt solder paste. The defining characteristic of laser soldering lies in its ability to harness the high energy density of laser beams to achieve instantaneous heating in localized or microscale areas, thereby completing the soldering process with exceptional precision. This technological breakthrough effectively resolves the longstanding challenges associated with welding in confined or miniature areas. When compared to conventional SMT welding processes, laser soldering demonstrates absolutely irreplaceable advantages!

Application Fields of Laser Solder Paste Welding: 

  Laser solder paste welding is typically employed for component reinforcement or pre-tinning applications. Typical use cases include reinforcing shield can corners through high-temperature solder paste melting, and contact point tinning for magnetic heads. The process is equally suitable for conductive circuit welding, demonstrating particularly outstanding performance in flexible printed circuit board (FPCB) applications. For instance, plastic antenna mounts - which don't involve complex circuitry - often achieve excellent results with solder paste welding. When it comes to precision micro-components, solder paste filling welding can fully demonstrate its technical advantages.

                  Dual-X/Dual-Y Dual-Station Solder Paste & Wire Feeding Welding System

The superiority of laser solder paste welding lies in its excellent heating uniformity and small equivalent diameter. When combined with precision dispensing equipment, it enables accurate control of solder paste volume for micro joints, effectively preventing spattering and thus ensuring superior welding quality.

However, the highly concentrated laser energy also presents challenges: uneven local heating of solder paste may cause explosive spattering. The splashed solder balls could potentially lead to circuit shorting risks. Consequently, this process demands exceptionally high-quality solder paste. To mitigate spattering issues, selecting anti-spatter solder paste proves to be an effective solution.

Currently, laser solder paste welding has found extensive applications, having been successfully implemented in precision electronic welding fields including:

• Camera modules

• VCM voice coil motors

• CCM (compact camera modules)

• FPC (flexible printed circuits)

• Connectors

• Antennas

• Sensors

• Inductors

• Hard disk drive heads

• Speakers/Horns

• Optical communication components

• Thermally sensitive components

• Photosensitive elements