The increasingly competitive market for electronic products has put significant pressure on electronic manufacturing companies in terms of quality and cost. The trend towards high density and miniaturization in electronic device production processes has propelled the rapid development of SMT (Surface Mount Technology) processes, with selective soldering experiencing a period of high-speed development. Below is an overview of the selective wave soldering process.
Selective wave soldering systems are mainly controlled by programs and consist of a multi-axis coordinated control platform equipped with flux nozzles and solder pots. After the PCB (Printed Circuit Board) is positioned and transported online via rails, flux is accurately sprayed onto the designated soldering positions on the PCB. Then, a precise ring-shaped mini solder wave is created using a small to medium-sized nozzle (typically 2~4mm in diameter) and a solder pump. Soldering is then performed from the bottom of the PCB using the multi-axis coordinated control platform. Since the electronic components to be soldered are usually surrounded by SMT components with high density and small spacing, the selective soldering process must be extremely precise to prevent damage to adjacent components and pads.
The program control of selective wave soldering systems is powerful, encompassing motion, process speed, unrestricted directional control (X, Y, Z), temperature, and heat control, among other aspects. During selective wave soldering, the soldering parameters for each solder joint can be customized, allowing ample room for process adjustments to optimize the soldering conditions (such as flux spraying volume, soldering time, soldering height, and wave height), thereby reducing defect rates. All control parameters can be saved in the program, allowing relevant data to be retrieved for each production run. Therefore, if the system is properly maintained, the soldering quality remains consistent even after several years.
Selective soldering differs significantly from traditional wave soldering. In traditional wave soldering, the entire PCB is completely immersed in the liquid solder. However, in selective soldering, only a specific area comes into contact with the solder wave, and adjacent electronic components and solder joints are not melted during soldering. In comparison to traditional wave soldering, flux is only accurately sprayed onto the designated soldering positions on the bottom of the PCB, rather than the entire PCB, thereby avoiding contamination of areas outside the solder joints.
