Notes on reflow temperature

Reflow welding system is to extract high temperature air containing a lot of flux from the preheating zone, reflow zone and cooling zone, after external cooling system, the clean gas is sent back to the furnace.

Notes for lead-free reflow curve setting

1. increase the preheating temperature In lead-free reflow welding, the preheating zone temperature of the reflow furnace should be higher than that of the preheating temperature of the tin/lead alloy reflow. It is usually about 30 ° C high, and the purpose of increasing the temperature of the preheating zone at 170 ° C-190 ° C (the traditional preheating temperature is generally 140 ° C-160 ° C) is to reduce the peak temperature to reduce the temperature difference between components.
2. Extend the preheating time Appropriate extension of the preheating time, preheating too fast on the one hand will cause thermal shock, is not conducive to reducing the temperature difference between the components in the formation of peak reflow temperature. Therefore, the preheating time of the preheating is properly extended, so that the temperature of the component to be welded smoothly rises to the predetermined preheating temperature.
3. extend the trapezoidal temperature curve of the reflow zone Extended trapezoidal temperature curve in the recirculation zone. While controlling the maximum reflow temperature, increase the temperature curve width of the reflow area, extend the peak time of small heat capacity components, so that the components with large and small heat capacity can reach the required reflux temperature, and avoid overheating of small components.
4. adjust the consistency of the temperature curve When testing and adjusting the temperature curve, although the temperature curve of each test point has a certain dispersion, it is impossible to be completely consistent, but it should be carefully adjusted to make the temperature curve of each test point as consistent as possible.