Laser Solder Paste Applications in Precision Laser Soldering Technology

Laser Solder Paste Applications in Precision Laser Soldering Technology

Industry professionals are well aware that solder paste is a creamy mixture composed of solder powder, flux, and other additives. At room temperature, the solder paste exhibits certain viscosity, enabling the temporary adhesion of electronic components to designated positions. During the soldering process, as solvents and some additives evaporate at elevated temperatures, the solder paste permanently bonds the components to the printed circuit board (PCB) pads.                                   

SMT assembly traditionally employs reflow soldering. While the contribution of reflow soldering to SMT is undeniable, cold solder joints remain the most common issue in the assembly process. However, with the maturation of laser technology, the combination of laser and solder paste has effectively addressed problems such as insufficient solder paste and cold joints in SMT production. Gradually, laser solder paste technology has gained recognition, and today, an increasing number of users are adopting laser solder paste welding equipment for manufacturing. So, what are the advantages of laser soldering with solder paste? And where is it applied?

Advantages of Laser Solder Paste Welding:

Laser soldering is a non-contact welding method, with soldering times as short as 300 milliseconds. The ultra-fast welding process prevents solvent volatilization and eliminates spattering during soldering, resulting in plump solder joints free from residual solder balls. Laser soldering is a technique that uses laser as the heat source to melt solder paste. Its primary characteristic lies in utilizing the high energy density of lasers to achieve rapid heating in localized or micro-scale areas, completing the soldering process and overcoming challenges in small or precise zone soldering. Compared to traditional SMT soldering, laser soldering offers irreplaceable advantages!

Applications of Laser Solder Paste Welding:

Laser solder paste welding is commonly used for component reinforcement or pre-tinning processes. For example, it can reinforce shield can edges by melting and solidifying solder paste at high temperatures, or apply soldering to magnetic head contacts. It is also well-suited for conductive circuit soldering, particularly excelling in flexible printed circuit (FPC) applications—such as plastic antenna mounts—where uncomplicated circuits often achieve excellent results through solder paste welding. For miniature precision components, solder paste filling welding fully demonstrates its advantages.

Due to solder paste's superior heat uniformity and relatively small equivalent diameter, precision dispensing equipment can accurately control micro-scale paste deposition. The paste resists splattering, ensuring high-quality solder joints. However, since laser energy is highly concentrated, uneven heating may cause explosive splattering, and scattered solder balls could lead to short circuits. To address this, semiconductor lasers equipped with built-in closed-loop power feedback control systems can effectively resolve solder paste heating inconsistency issues.

Songsheng Photoelectric Temperature Closed-Loop Feedback Control System (Built-in Laser System)

The Songsheng Photoelectric Laser Constant-Temperature Soldering System integrates a real-time temperature feedback system, CCD coaxial alignment system, and semiconductor laser. Featuring an innovative PID online temperature regulation feedback system, it effectively maintains constant-temperature soldering with high-precision real-time temperature control of soldering targets, ensuring superior soldering yield and precision.

Currently, laser solder paste welding has found extensive applications across various precision electronics 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 & buzzers

• Optical communication components

• Thermally sensitive components

• Photosensitive components