With the development of e-mobility, copper welding is gaining importance as a research field, since copper is a key component of electrical subsystems such as batteries and power electronics. Laser welding of copper presents a significant challenge due to its high reflectivity and temperature-dependent material characteristics. In this work, we develop a system for controlling the width of laser welding of copper using a 3 kW fiber laser. The system operates on the basis of an optical feedback loop, where a camera monitors the weld and measures the width of the welding zone. Based on the measured and desired weld width, a PID controller adjusts the welding power. We developed four controllers and tested the combined use of different controllers simultaneously. The results showed that the optical feedback loop can control the welding width with a standard deviation between 2 % and 10 %. The fastest change in welding width was achieved using a feed-forward PID controller, which required 0.02 seconds to adjust the width. The system enables faster process setup, better process control, and higher-quality welding compared to conventional copper laser welding systems.
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