How can the laser soldering machine not burn the substrate
First of all, we should know that laser welding is an efficient and precise welding method using high energy density laser beam as the heat source. From here, we can understand some of the reasons why the laser soldering machine burns the substrate.
Problem 1: High-energy local rapid heating leads to thermal expansion and deformation of the solder joint copper foil, and the solder joint copper foil is separated from the substrate.
Solution: The first welding point is heated from low temperature to high temperature continuously and steadily. For example, the welding process of the welding point requires a temperature of 350 ℃, so we can set the temperature to rise from 280 ℃ to 350 ℃ for 0.3S, which can generally solve this problem.
Problem 2: The controller of the laser soldering machine adopts the power mode, and there is no professional laser engineer to adjust it.
The power mode is to continuously output energy to the solder joint according to the set output power, regardless of the actual welding temperature. Power mode is suitable for solder joints with fast heat dissipation.
Solution: At present, laser soldering adopts closed loop control, and non-special solder joints generally adopt temperature mode.
Problem 3: The temperature of the laser soldering machine is overloaded under the temperature mode, which exceeds the set welding temperature.
We know that the current laser soldering machine adopts closed-loop control system. After setting the temperature, the controller will automatically calculate the required output power. The calculation of power is to collect real-time temperature. Temperature acquisition is the most important part of the closed-loop control of the laser soldering machine.
The temperature overload is because the temperature feedback is not timely enough, resulting in the controller continuously increasing the output energy in order to obtain the feedback temperature.
Solution 1: adopt laser soldering machine with more sensitive temperature feedback. At present, the feedback of laser soldering machine in China is 1000 times/s. The laser soldering module imported from Germany is adopted by Yuli Automation, and the feedback is 10000 times/s, up to 15000 times/s.
Solution 1: add power limit in temperature mode. As mentioned above, temperature overload in temperature mode is caused by untimely feedback, so we can observe the output power of the overload place with more temperature curve to limit the output power, which can also solve the overload problem.
