1. There are two different selective welding processes: drag welding and dip welding.
2. The selective drag welding process is performed using a single small-tip solder wave. It is particularly suitable for welding in very confined spaces on a PCB. For instance, individual solder joints or pins, as well as single row pins, can undergo the drag welding process. The PCB moves across the solder wave of the nozzle at various speeds and angles to achieve optimal welding quality. To ensure welding stability, the inner diameter of the welding nozzle is kept below 6mm. After determining the direction of the solder solution, solder nozzles are installed and optimized in different directions to accommodate various welding needs. The manipulator can approach from different angles, ranging between 0° to 12° relative to the solder wave. This flexibility allows users to weld a variety of devices onto electronic components, with the recommended inclination angle for most devices being 10°.
3. Compared to the dip welding process, the drag welding process offers better heat conversion efficiency due to the solder solution and PCB board movement. However, the heat required to form the weld joint is transferred through the solder wave. Since the mass of the solder wave from a single nozzle is small, only the temperature of the solder wave is relatively high to meet the requirements of the drag welding process. For instance, a solder temperature range of 275℃ to 300℃ and a drag speed of 10mm/s to 25mm/s are typically acceptable. Nitrogen is supplied in the welding area to prevent oxidation of the solder waves, thereby eliminating oxidation and avoiding the generation of bridge defects in the drag welding process. This advantage enhances the stability and reliability of the drag welding process.
4. The machine boasts high precision and flexibility. Its modular structure design system can be fully customized according to the customer’s specific production requirements and can be upgraded to meet future production developments. The manipulator’s radius of motion covers the flux nozzle, preheat, and solder nozzle, enabling different welding processes on the same equipment. The machine’s unique synchronous process significantly reduces the single-board process cycle. The manipulator excels in performing selective welding with high precision and high-quality welding characteristics. Firstly, it ensures precise positioning with height stability (±0.05mm) to maintain consistent production height parameters for each plate. Secondly, the manipulator’s five-dimensional motion enables the PCB to make optimized contact with the tin surface at any angle and orientation for the best soldering quality. A tin wave height measuring needle, made of titanium alloy, is installed on the splint device of the manipulator. Controlled by the program, it regularly measures the tin wave height, which can be adjusted by varying the rotating speed of the tin pump to ensure process stability.
5. Despite these advantages, the single-tip wave tow process has its drawbacks. It has the longest welding time among the three processes: flux spray, preheat, and soldering. Additionally, because solder spots are drag-welded one by one, the welding time significantly increases with the number of solder spots, resulting in lower welding efficiency compared to the traditional wave soldering process. However, this scenario is changing, with multiple nozzles designed to maximize production. For example, double nozzles can double production, and double nozzles can be used for flux.
6. The immersion selective welding system features multiple solder nozzles designed one-to-one with the PCB solder spots. While it may lack the flexibility of the manipulator type, its output matches that of traditional wave soldering equipment, and its equipment cost is lower. Depending on the PCB size, single or multiple plates can be transferred in parallel, and all pending solder joints are fluxed, preheated, and soldered simultaneously. However, due to the varying distribution of solder joints on different PCBs, special solder nozzles must be made for different PCBs. It is crucial and challenging for design engineers to keep the size of the weld nozzles as large as possible to ensure welding process stability without affecting surrounding components on the PCB, as process stability may depend on it.
7. Using the immersion selective welding process, welding joints ranging from 0.7mm to 10mm can be welded. The welding process of short pins and small-sized pads is more stable, with a lower likelihood of bridging. The distance between adjacent solder joint edges, devices, and welding nozzles should be greater than 5mm.
2. The selective drag welding process is performed using a single small-tip solder wave. It is particularly suitable for welding in very confined spaces on a PCB. For instance, individual solder joints or pins, as well as single row pins, can undergo the drag welding process. The PCB moves across the solder wave of the nozzle at various speeds and angles to achieve optimal welding quality. To ensure welding stability, the inner diameter of the welding nozzle is kept below 6mm. After determining the direction of the solder solution, solder nozzles are installed and optimized in different directions to accommodate various welding needs. The manipulator can approach from different angles, ranging between 0° to 12° relative to the solder wave. This flexibility allows users to weld a variety of devices onto electronic components, with the recommended inclination angle for most devices being 10°.
3. Compared to the dip welding process, the drag welding process offers better heat conversion efficiency due to the solder solution and PCB board movement. However, the heat required to form the weld joint is transferred through the solder wave. Since the mass of the solder wave from a single nozzle is small, only the temperature of the solder wave is relatively high to meet the requirements of the drag welding process. For instance, a solder temperature range of 275℃ to 300℃ and a drag speed of 10mm/s to 25mm/s are typically acceptable. Nitrogen is supplied in the welding area to prevent oxidation of the solder waves, thereby eliminating oxidation and avoiding the generation of bridge defects in the drag welding process. This advantage enhances the stability and reliability of the drag welding process.
4. The machine boasts high precision and flexibility. Its modular structure design system can be fully customized according to the customer’s specific production requirements and can be upgraded to meet future production developments. The manipulator’s radius of motion covers the flux nozzle, preheat, and solder nozzle, enabling different welding processes on the same equipment. The machine’s unique synchronous process significantly reduces the single-board process cycle. The manipulator excels in performing selective welding with high precision and high-quality welding characteristics. Firstly, it ensures precise positioning with height stability (±0.05mm) to maintain consistent production height parameters for each plate. Secondly, the manipulator’s five-dimensional motion enables the PCB to make optimized contact with the tin surface at any angle and orientation for the best soldering quality. A tin wave height measuring needle, made of titanium alloy, is installed on the splint device of the manipulator. Controlled by the program, it regularly measures the tin wave height, which can be adjusted by varying the rotating speed of the tin pump to ensure process stability.
5. Despite these advantages, the single-tip wave tow process has its drawbacks. It has the longest welding time among the three processes: flux spray, preheat, and soldering. Additionally, because solder spots are drag-welded one by one, the welding time significantly increases with the number of solder spots, resulting in lower welding efficiency compared to the traditional wave soldering process. However, this scenario is changing, with multiple nozzles designed to maximize production. For example, double nozzles can double production, and double nozzles can be used for flux.
6. The immersion selective welding system features multiple solder nozzles designed one-to-one with the PCB solder spots. While it may lack the flexibility of the manipulator type, its output matches that of traditional wave soldering equipment, and its equipment cost is lower. Depending on the PCB size, single or multiple plates can be transferred in parallel, and all pending solder joints are fluxed, preheated, and soldered simultaneously. However, due to the varying distribution of solder joints on different PCBs, special solder nozzles must be made for different PCBs. It is crucial and challenging for design engineers to keep the size of the weld nozzles as large as possible to ensure welding process stability without affecting surrounding components on the PCB, as process stability may depend on it.
7. Using the immersion selective welding process, welding joints ranging from 0.7mm to 10mm can be welded. The welding process of short pins and small-sized pads is more stable, with a lower likelihood of bridging. The distance between adjacent solder joint edges, devices, and welding nozzles should be greater than 5mm.
