Laser butt welding of thin steel sheets without filler material was widely used in many industrial fields. However. it was very difficult to focus the small laser spot on the narrow gap between the sheets during the laser butt welding process. In this study. https://www.nacrack.com/hot-choice-Open-Box-Verona-Wig-by-BelleTress-Heat-Friendly-Synthetic-Hair-Average-Cap-Buttered-Toast-R-great-buy/