Analysis of the influence of laser process parameters on cutting performance of laser-assisted disc cutter

Abstract

Laser-assisted disc cutter cutting offers a promising approach to enhance the cutting performance of hard rock by inducing thermal stress, which weakens the rock’s strength. In this study, experiments and numerical simulations were conducted to establish the relationship between laser-induced thermal stress and rock strength weakening. The effects of laser power, radiation distance, and strafing speed on the weakening of rock strength and energy consumption in granite were investigated, providing an optimal process window for laser-assisted disc cutter cutting. An experimental system for synchronous laser-disc cutter cutting was developed to examine the influence of laser parameters on cutting performance. Results indicate that the weakening of granite strength is closely associated with laser-induced thermal stress. Higher laser power, coupled with lower strafing speed and shorter radiation distance, significantly enhances thermal cracking in the granite, leading to more effective induction of thermal stress and, consequently, greater weakening of rock strength. The maximum reduction in rock strength observed was 41.34 %. However, excessive heat absorption by the granite can cause melting and evaporation, increasing energy loss. Thus, it is crucial to determine an optimal balance between maximum strength reduction and minimal energy consumption for granite in laser-assisted disc cutter cutting. Compared with conventional rock cutting, laser-assisted disc cutter cutting reduces normal cutting force from 11.488 kN to 9.638 kN, a decrease of 16 %. Additionally, normal vibration acceleration is reduced from 18.881 mm/s² to 14.432 mm/s², representing a 23 % reduction. The volume of rock broken increases from 13.50 cm³ to 16.50 cm³, reflecting a 22.22 % improvement. These findings demonstrate that laser-assisted disc cutter cutting reduces the load impact on the disc cutter and enhances rock-cutting volume. Further analysis of lithological energy under laser-assisted conditions is essential for improving the cutting performance of Tunnel Boring Machine (TBM).