Single sided cooling structure of reflow soldering cooling zone

Reflow soldering gas control

Gas control includes two aspects, one is the addition of gas required for reflow welding and the emission of exhaust gas in the furnace. Gas injection can be divided into two types: nitrogen (N2) and compressed air. The nitrogen furnace is tightly sealed to prevent oxygen from entering the furnace. The oxygen content is the key to a nitrogen furnace, and its size affects the quality of component welding. The oxygen content in the furnace area can be accurately measured by connecting the oxygen content tester to the sampling port of the furnace body. A good furnace can have an oxygen content of less than 50PPM [6]. When nitrogen is not needed, compressed air should be injected into the furnace to maintain the required gas content. The exhaust gas inside the furnace (including volatiles of flux and waste smoke generated by large-scale reflow welding) should be continuously discharged outside the furnace to maintain a normal gas environment inside the furnace and protect the health of operators. The exhaust pipe of the furnace body should be connected to the exhaust device of the entire factory.

Reflow soldering conveyor belt structure

There are generally two types of product conveying devices for reflux furnaces: mesh conveyor belts and track conveyor belts. Users can choose according to their product needs. The general reflux furnace is equipped with both types of conveyor belts for the convenience of users. The speed of the conveyor belt is programmable and determined. Due to the direct impact of belt speed on the temperature curve of reflow soldering. Therefore, the stability of the belt speed is crucial. The speed control of the reflow soldering furnace is also a closed-loop control system. Control the speed of the conveyor belt by controlling the speed of the drive motor.

In addition to the stability of the belt speed, the smoothness of the mechanical movement of the conveyor belt is also important. Because during the melting process of reflow soldering, the vibration of the conveyor belt can cause welding defects, such as component misalignment, virtual soldering, and dropped parts. The key to ensuring mechanical stability lies in the maintenance and upkeep of the conveying mechanism. The cleaning and lubrication of chains and gears, as well as the maintenance of DC motor brushes, are all very important. The conveyor belt is also equipped with an uninterruptible power supply (UPS), which can maintain the operation of the conveyor belt for 5-10 minutes in case of unexpected power interruption of the entire furnace, until all PCB boards in the furnace are sent out, avoiding board burning accidents.