Relevant precautions for wave soldering operation in PCBA processing

In production, if there is a large amount of solder after welding, it is necessary to choose wave soldering for processing. When operating wave soldering, attention should be paid to:

The wave crest surface is covered by a layer of oxide skin, which remains almost static along the entire length of the solder wave. During the wave soldering process, the PCB contacts the front surface of the tin wave, causing the oxide skin to break and the tin wave in front of the PCB to be pushed forward without wrinkles. This indicates that the entire oxide skin moves at the same speed as the PCB.

In general, to avoid poor soldering during wave soldering, the following methods can be used: using solderable components/PCB, improving the activity of the solder joint, increasing the preheating temperature of the PCB, increasing the wetting performance of the solder pad, increasing the temperature of the solder, removing harmful impurities, and reducing the cohesion of the solder, in order to facilitate the separation of the solder between two solder joints.

Common preheating methods in wave soldering machine: air convection heating, infrared heater heating, hot air and radiation heating; Wave soldering process curve analysis: wetting time refers to the time when wetting begins after the solder joint comes into contact with the solder, residence time refers to the time when a solder joint on a PCB moves from the contact wave surface to the departure from the wave surface, preheating temperature refers to the temperature reached before the PCB comes into contact with the wave surface, and welding temperature refers to the welding temperature, which is a very important welding parameter. Usually, it is 50 ° C to 60 ° C higher than the melting point of solder (183 ° C). In most cases, it refers to the temperature of the PCB solder joint welded during actual operation of the soldering furnace being lower than the furnace temperature, which is due to the heat absorption of the PCB.