What is a wave soldering machine-Special Wave Soldering Finger Resin claw

1. What is a wave soldering machine:
Welding technology is the core of PCBA production and the key to determining the quality of PCBA products. Currently, there are two main types that are widely used and continuously improved: wave soldering and reflow soldering.
One of the devices that first appeared on the market to provide dense gap soldering of surface mount components was the dual wave soldering system. The dual wave soldering system can generate two wave crests: the first shock wave and the second smooth wave.
2. Principle and structure of wave soldering:
The wave soldering machine is mainly composed of a conveyor belt, a flux adding zone, a preheating zone and a wave soldering furnace.
The main purpose of the conveyor belt is to feed the circuit board into the wave soldering machine, passing through the flux adding area, preheating area, and wave soldering furnace along the way.
The flux addition area is mainly composed of infrared sensors and nozzles. The function of the infrared sensor is to sense whether there is a circuit board entering. If there is a sensor, it will measure the width of the circuit board. The function of the flux is to form a protective film on the soldering surface of the circuit board.
The preheating zone provides enough temperature to form a good solder joint. Infrared heating can make the circuit board heat evenly,
In the dual wave soldering system, the shock wave part of the wave prevents solder leakage, and it ensures proper distribution of solder through the circuit board. The solder penetrates through the slit at a relatively high speed, thereby penetrating a narrow gap. The spray direction is the same as the direction of the circuit board. The shock wave alone cannot properly solder the components. It leaves unevenness and excess solder on the solder joints, so a second wave is needed.
The second smooth wave eliminates the burrs and solder bridges caused by the first shock wave. The smooth wave is actually the same as the wave used in traditional through-hole inserts. Therefore, when the traditional components are welded on a machine, the shock wave can be turned off and the traditional components can be welded with a smooth wave.
Introduction to the principle of wave soldering
Wave soldering is to use molten liquid solder to form a solder wave of a specific shape on the liquid surface of the solder tank with the help of a pump. The PCBA with the components inserted is placed on the conveyor chain through a specific angle and a certain immersion. The process of deep penetration of solder wave peaks to achieve solder joint soldering.
The surface of the wave crest is covered by a layer of oxide scale, which remains static almost along the entire length of the solder wave. During the wave soldering process, the PCB touches the front surface of the tin wave, the oxide scale is broken, and the tin in front of the PCBA The wave is pushed forward without folds, which means that the entire oxide scale moves at the same speed as the PCB to form the solder joints of the wave soldering machine: When the PCBA enters the front end (A) of the wave crest surface, the substrate and the pins are heated, and the Before leaving the wave surface (B), the entire PCB is immersed in the solder, that is, bridged by the solder, but at the moment of leaving the end of the wave, a small amount of solder adheres to the pad due to the wetting force, and due to the surface The reason for the tension is that the shrinkage is minimized with the lead as the center. At this time, the wetting force between the solder and the pad is greater than the cohesion of the solder between the two pads. Therefore, a full and round solder joint will be formed, and the excess solder leaving the tail of the wave will fall back into the tin pot due to gravity. Prevent the occurrence of bridging.
1. Use components/PCB with good solderability
2. Improve the activity of flux
3. Increase the preheating temperature of the PCB and increase the wetting performance of the pad
4. Increase the temperature of the solder
5. Remove harmful impurities and reduce the cohesion of the solder to facilitate the separation of the solder between the two solder joints.
Common preheating methods in wave soldering machines
1. Air convection heating
2. Infrared heater heating
3. Heating by a combination of hot air and radiation
Analysis of wave soldering process curve
1. Wetting time
Refers to the time when the wetting starts after the solder joint contacts the solder
2. Stay time
The time from touching the crest surface to leaving the crest surface of a solder joint on the PCB
The calculation method of dwell/welding time is:
Dwell/welding time = wave crest width/speed
3. Preheating temperature of wave soldering
The preheating temperature refers to the temperature reached before the PCB contacts the wave crest surface (see the table on the right)
4. Wave soldering temperature
The soldering temperature is a very important soldering parameter, usually 50°C~60°C higher than the melting point of the solder (183°C). In most cases, it means that the temperature of the soldering furnace is actually lower than the temperature of the soldering point of the PCB. Warm, this is because the PCB absorbs heat
Preheating temperature of SMA type components
Single-panel components through-hole devices and mixed 90~100
Through hole device for double panel assembly 100~110
Double panel components mixed 100~110
Multi-layer board through hole device 115~125
Multi-layer board mixed 115~125