Influence of reflux furnace equipment characteristics on temperature curve

Reflow soldering temperature curve is realized in reflow soldering equipment, so reflow soldering temperature curve will be affected by the characteristics of reflow soldering. Different reflow soldering furnaces will affect the reflow soldering temperature curve due to the number and length of heating zones, the size of air flow and the capacity of furnace temperature.

1、 Influence of heating zone number of reflow soldering equipment on temperature curve

For reflow soldering furnaces with many heating zones (8 heating zones), since each furnace zone can set the furnace temperature separately, it is easier to adjust the reflow temperature curve. The reflow soldering temperature curve with complex requirements can also be achieved. However, small reflow soldering equipment (less temperature zone), because it has only four adjustable temperature zones, it is difficult to obtain complex curves, but for SMT welding without special requirements, small reflow soldering equipment can also meet the requirements, and the price is cheap. On the other hand, the advantage of large reflow soldering equipment is that the belt speed of the conveyor belt can be at least twice as high as that of small reflow soldering equipment, so that the output of large reflow soldering equipment can be at least twice as high as that of small reflow soldering equipment. This is crucial when mass production lines pursue capacity.

2、 Influence of hot air flow of reflow soldering equipment on temperature curve

At present, most reflow soldering equipment is mainly driven by the fan to force the hot air circulation, so the fan speed determines the air volume. Under the same belt speed and the same temperature setting, the higher the speed of the fan, the higher the temperature of the reflux curve. When the fan motor fails, if it stops running, even if the furnace temperature display is normal, the reflow soldering temperature curve measurement will be much lower than the normal curve. If the faulty motor is in the reflow area, the PCB board is prone to cold soldering. If the faulty motor is in the cooling area, the cooling effect of the PCB board will decline. Therefore, the motor speed is a programmable reflow soldering device, and the fan speed is also one of the parameters that need to be checked frequently.

3、 Influence of furnace temperature capacity of reflow soldering equipment on temperature curve

Reflow soldering sometimes occurs. When a small size PCB is welded, the welding result is very good, while when a large size PCB is welded, the furnace temperature in some temperature zones will drop slightly. This is because the large plate absorbs more heat and the heat capacity of the furnace is insufficient. Generally, it can be adjusted by increasing the fan speed. However, the capacity of the furnace temperature is mainly determined by the furnace structure, heater power and other design factors, so it has been fixed by the reflow equipment manufacturer when designing. Users must consider this factor when choosing reflow soldering equipment. The larger the heat capacity, the better. Of course, the more power the furnace consumes.