Parameter setting modification of reflow transport speed

In the reflow soldering process of circuit board, too fast or too slow reflow soldering transportation speed parameters will make the components experience too long or too short heating time, resulting in the volatilization of flux and the change of solder joint tin eating ability. Missing the allowable heating rate of components will also cause a certain degree of damage to the components. Editor in chief, let's share the parameter setting modification of reflow soldering transportation speed:

1. The setting of transportation speed is determined according to the time required for the temperature curve provided by the solder paste supplier. Generally, the whole process of large plate welding such as main board is 5-6.5min, and the whole process of small plate welding is 3.5-5min. The shorter the furnace length, the lower the transportation speed setting; The longer the furnace chamber length, the higher the transportation speed setting. The setting principle is to ensure that the time of PCB passing through the furnace corresponds to the time required by the temperature curve.

2. The temperature setting of the heating module in each temperature zone is also determined according to the temperature curve of the solder paste supplier. The temperature in the temperature zone is set according to the rising / falling slope, time requirements and peak temperature of the temperature curve. The larger the rising slope is, the higher the peak temperature is, the higher the temperature setting is. On the contrary, the lower it is, and the maximum temperature setting value cannot exceed the limit value that the furnace can withstand 300 ℃.

3. For the same temperature curve, the set values of temperature and speed may still be different when producing different PCBs, which is related to the heat absorption of PCB. The thicker the PCB and the larger the components, the higher the temperature value set by the process reaching the same temperature curve, which can also be solved by reducing the transportation speed. On the contrary, reduce the set temperature or increase the transportation speed.