Laser cutting: a comparison of the performance of Gaussian, donut and top-hat beams, and an explanation of factors affecting cut quality and striation generation as a function of cutting speed

Abstract The influence of different laser energy distributions (Gaussian, donut, and top-hat) on cutting speed, burr formation, and striation pattern/roughness in laser cutting was investigated. While the maximum cutting speeds are nearly identical for all beam profiles, cut quality varies significantly with cutting speed. The top-hat beam produces good quality cuts at high cutting speeds. However, at low cutting speeds, burr formation and oxidation occur due to a separation of the gas flow from the melt in divergent kerf geometries (as confirmed by CFD simulations). The Gaussian and donut beams produce good quality cuts at low speeds but lead to resolidified melt retention on the kerf walls at high speeds that degrade the edge quality. The underlying factors which determine the differences in the cut quality produced by the various laser beams is discussed in detail.