Ultraviolet Nanosecond Laser-Ablated Groove Analysis of 2.5D Cf/SiC Composites

Abstract

The 2.5D Cf/SiC composite is a typical heterogeneous material with the characteristics of anisotropy, which makes it difficult to predict the size and damage removed by the traditional contact removal process. This paper adopted the ultraviolet nanosecond laser to ablate the Cf/SiC composites by considering the heterogeneous structure’s effect. The ablated groove topography and size prediction are effective in revealing the machined quality with predictable groove sizes. The effects of laser processing parameters on the groove morphology and surface thermally affected zone are investigated with the thermal removal mechanism. A regression model is established by considering the scanning times, scanning speed, laser power and pulse width as the main variables. In the regression models, the relative error values are all below 10%. It is revealed that the groove width diminishes with the scanning speed and increases as the laser power increases. However, the influence of the scanning times and pulse width is small, and the overall variation range is within ±10 μm. The results show that the arrangement direction of carbon fibers has an impact on laser processing, especially when the pulse width is 0.25 μs, upon which the opposite change occurs. Carbon fiber grooves are not obvious and are barely observed in the laser processing of the parallel carbon fiber direction, and the grooves are slightly uneven. This study could be helpful in analyzing the grooves of Cf/SiC affected by the laser processing process, which could support the hybrid machining of the Cf/SiC composites.