The laser welding machines currently on the market are mainly divided into two categories in terms of control characteristics: current negative feedback and laser power negative feedback.
Current negative feedback is a control method that controls the current of the laser pumped xenon lamp to keep the xenon lamp current constant every time. However, the laser output power is not linearly proportional to the current of the pumped xenon lamp, and with the use of the pumped xenon lamp, the electro-optical conversion efficiency is significantly reduced, which will reduce the output laser energy, thereby affecting the consistency of the welding effect Sex.
Laser power negative feedback is a control method that adds a photodetector at the output of the laser cavity, compares the detected laser power with the required laser power, and then controls the magnitude of the xenon lamp pumping current. Laser power negative feedback is divided into real-time negative feedback and non-real-time negative feedback. Real-time negative feedback is a control method that compares the detected laser power with the required laser power in a laser power pulse, and then controls the magnitude of the xenon lamp pumping current. Non-real-time negative feedback is a control method that compares the laser power waveform detected by the previous pulse with the set waveform and then determines the current magnitude of the laser pulsed xenon lamp for the next pulse.
Compared with current negative feedback control, using laser power negative feedback, the control accuracy of output laser energy can be greatly improved, especially suitable for mass production.
