The Importance of Soldering Precision and Accurate Temperature Control in Laser Soldering

The Importance of Soldering Precision and Accurate Temperature Control in Laser Soldering

Over the past decade, the 3C electronics and optical communication industries have experienced rapid development, with electronic components becoming increasingly miniaturized. Traditional SMT equipment and contact soldering methods can no longer meet the requirements of modern electronic and microelectronic soldering processes. High-precision, high-efficiency, non-contact laser soldering equipment has gradually become an industry focus.

Songsheng Optoelectronics has accurately identified market demands and conducted in-depth research in the field of laser soldering. The company has developed a constant-temperature laser soldering system (for solder paste dispensing and wire feeding) that perfectly meets market needs. This system provides the industry with a completely new laser welding solution, significantly improving the processing efficiency and yield of precision optoelectronic devices.

Optical Communication Products and Laser Soldering Applications

Optical communication products are increasingly evolving toward diversified integration. For instance, in optical module soldering, solder joints are numerous and densely arranged. Songsheng Optoelectronics' laser soldering system effectively addresses the issues associated with thermal compression bonding, including the impact of heat spreader dissipation zones on surrounding components and the risk of overheating on the backside of pads.

When using laser as the heat source for soldering, the flexibility of laser energy delivery enables minimal thermal shock to peripheral components.

Illustration of temperature profile changes in a temperature-controlled laser soldering system

Advantages of Temperature Control in Laser Soldering Compared to Other Market Systems

The laser soldering system from Songsheng Optoelectronics achieves precise temperature control and real-time monitoring, a capability refined through extensive time and experience.

The key function of its temperature feedback system is to real-time monitor and adjust the temperature at the soldering point, ensuring it remains within the set range to prevent overheating and solder joint damage.

This system enables precise control over temperature variations during the soldering process, ensuring both welding quality and efficiency.

Specifically, the temperature feedback system achieves localized temperature regulation in the soldering zone, capable of controlling a 1mm-diameter micro-area with a precision of ±2°C.

Moreover, the system incorporates a proprietary PID-based real-time temperature adjustment technology, further enhancing control accuracy and thermal stability.

The laser energy control system is responsible for adjusting the output power of the laser to accommodate different soldering requirements. Utilizing closed-loop control technology, this system achieves precise laser energy modulation, thereby optimizing the soldering process and improving both quality and yield rates.

When integrated with the temperature feedback system, it forms a high-efficiency, reliable soldering control system capable of meeting diverse production environment demands.

Working Principle Analysis of Coaxial Infrared Temperature Measurement System and PID Algorithm

Coaxial Infrared Temperature Measurement System
The coaxial infrared temperature measurement system is an optoelectronic sensor that detects the infrared radiation emitted by a target object and converts it into an electrical signal. Through electronic circuit amplification, linearization, and signal processing, the system displays or outputs the temperature value. This system is particularly suitable for measuring metals and other materials, enabling non-contact surface temperature measurement by calculating the intensity of infrared radiation emitted from the target.

PID (Proportional-Integral-Derivative) Control Algorithm
The PID control algorithm is a widely used closed-loop feedback control method. It generates a control signal by linearly combining the proportional (P), integral (I), and derivative (D) components of the error signal to achieve precise system control. Specifically:

• Proportional Control (P): The proportional parameter Kp adjusts the output based on the current error signal, providing an immediate response proportional to the temperature deviation.

• Integral Control (I): The integral parameter Ki accounts for the accumulated past errors, eliminating steady-state deviations by integrating the error over time.

• Derivative  Control (D): The derivative parameter Kd predicts future error trends based on the rate of change of the error, improving         system stability and response speed.

This combined approach ensures high-precision temperature regulation in dynamic soldering processes.

Songsheng optoelectronics constant temperature laser soldering system diagram

  Songsheng Optoelectronics Constant Temperature Laser Soldering System is composed of multi-axis servo modules, real-time temperature feedback system, CCD coaxial alignment system and semiconductor laser. Through years of soldering process development, we have independently developed intelligent constant temperature soldering software that supports importing multiple file formats. The innovative PID online temperature regulation feedback system effectively controls constant temperature soldering, ensuring high yield rate and precision. The system features a four-point coaxial design integrating laser, infrared guiding light, CCD and infrared temperature measurement. The coaxial CCD automatically locates solder joints while the infrared temperature measurement provides real-time feedback on solder point temperature. The PID algorithm precisely and stably adjusts laser power through proportional, integral and derivative control based on temperature measurements, maintaining solder point temperature within the set range. The X, Y, Z axis configuration accommodates welding of various components, enabling wider applications.

  In summary, the high precision and accurate temperature control of laser soldering play a crucial role in enhancing production efficiency and product quality in the electronics manufacturing industry. These technological advantages not only improve China's R&D capabilities and production yield of high-end interconnection products, but also break the foreign monopoly on specialized equipment for advanced electronic assembly. Therefore, continued optimization and innovation in laser soldering technology will remain a key direction for the future development of the electronics manufacturing sector.