Analysis and optimization of traveling wave of large diamond core drill bit

For the vibration and noise issues that occur during drilling of large diamond core drill bits, modal analysis was conducted using Ansys Workbench finite element software on core drill bits without openings, openings, interlayers, and installation of positioning wheels. Furthermore, the resonance margin/δ of core drill bits was calculated using traveling wave vibration theory to analyze the effect of avoiding traveling wave resonance. Study the influence of openings and interlayers on traveling wave vibration. The results show that when the drilling speed is 186.72 r/min, the δ of the no opening core drill bit is 0, and a backward traveling wave resonance occurs. In the area where there is a large deformation of the inherent mode of traveling wave resonance in the no opening core drill bit, the δ of opening 8 sets of circular holes (3 in each group) and 8 S-shaped holes in the core drill bit is 4.97%, which avoids traveling wave resonance effectively; The δ of the opening and sandwich core drill bit is 5.72%, which has the best effect of avoiding traveling wave resonance. In order to improve the accuracy of machining holes, positioning wheels are installed around the core drill bit, and the impact of the number of positioning wheels on traveling wave vibration is analyzed. Among them, the δ of installing 6 and 12 positioning wheel core drill bits is 4.27% and 4.47%, respectively, to avoid traveling wave resonance. Comparing the δ of 2 to 12 positioning wheel core drill bits and considering installation convenience, the optimal number of positioning wheels for installation is finally determined to be 6.