Visual-assisted laser microwelding of carbon microfiber on metal plates

The welding scale of laser welding now went to micrometer size. Under the view of optical microscopy, the high-precision laser welding systems can be achieved. But the welding processes were monitored by human eyes, and the light scattering may interfere the observation. We presented a visual-assisted laser microwelding system. This work combined laser microwelding technology, thermal imaging process, and the active feedback control loop to achieve the real-time microwelding quality control. The thermal imaging camera and the near infrared CCD camera were used to monitor the welding process. The active feedback control loop was employed, and linked the thermal distribution of the thermal images with the duty cycle of laser operations. 0.1-s response time can make sure the laser welding under control without manually tuning. So that welding technicians with this optical system can control the quality, improve the production yields, and shorten the whole process time. With this optical system, we successfully welded the carbon strip and tens-of-µm carbon fiber with aluminum plate. It will be useful for soft, and flexible carbon-based electrical devices.