There are two different processes for selective soldering process: drag soldering process and dip soldering process.
The selective drag soldering process is completed on a single small soldering tip solder wave. The drag soldering process is suitable for soldering in very tight spaces on the PCB. For example: individual solder joints or pins, single-row pins can be drag soldered. The PCB moves on the solder wave of the soldering tip at different speeds and angles to achieve the best soldering quality. In order to ensure the stability of the welding process, the inner diameter of the welding tip is less than 6mm. After the flow direction of the solder solution is determined, the soldering tips are installed and optimized in different directions for different soldering needs. The manipulator can approach the solder wave from different directions, that is, at different angles between 0° and 12°, so users can solder various devices on electronic components. For most devices, the recommended tilt angle is 10°.
Compared with the dip soldering process, the solder solution of the drag soldering process and the movement of the PCB board make the heat conversion efficiency during soldering better than that of the dip soldering process. However, the heat required to form the weld connection is transferred by the solder wave, but the solder wave quality of a single solder tip is small. Only the relatively high temperature of the solder wave can meet the requirements of the drag soldering process. Example: The solder temperature is 275℃～300℃, and the pulling speed is usually 10mm/s～25mm/s. Nitrogen is supplied in the welding area to prevent the solder wave from oxidizing. The solder wave eliminates the oxidation, so that the drag soldering process avoids the occurrence of bridging defects. This advantage increases the stability and reliability of the drag soldering process.
The machine has the characteristics of high precision and high flexibility. The modular structure design system can be fully customized according to the customer’s special production requirements, and can be upgraded to meet the needs of future production development. The radius of motion of the manipulator can cover the flux nozzle, preheating and soldering nozzle, so the same equipment can complete different welding processes. The machine’s unique synchronization process can greatly shorten the single board process cycle. The capabilities of the manipulator make this selective welding have the characteristics of high-precision and high-quality welding. Firstly, the highly stable and precise positioning capability of the manipulator (±0.05mm) ensures that the parameters produced by each board are highly repetitive. Secondly, the 5-dimensional movement of the manipulator enables the PCB to contact the tin surface at any optimized angle and orientation to obtain the best Good welding quality. The tin wave height stylus installed on the manipulator splint device is made of titanium alloy. The tin wave height can be measured regularly under program control. The tin wave height can be controlled by adjusting the tin pump speed to ensure process stability.
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