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In order to improve the rock-breaking efficiency in hard rock formations, this paper presents an impregnated diamond bit with a special matrix structure. The grid-shaped matrix is designed to achieve large volume breakage so that the rock breaking efficiency can be greatly improved. The calculated specific pressure on the bottom surface lip of the newly proposed bit increased by 67%, from 68 kgf/cm2 to 113 kgf/cm2, compared to the conventional impregnated diamond bit. In such case, the grid piece can be effectively pressed into rocks to produce more cracks to effectively break them. In this paper, to study the rock-breaking mechanism of this impregnated diamond bit with grid-shaped matrix (IDBGM), subjected to different grid spacing and rock properties, rock cutting tests were conducted by using a TXCB-5P precision microtome and two 3D-printed grid pieces. The results indicate that the optimum grid spacing is 2 mm, because of the largest-scale cuttings when breaking rock ridges produced by the proposed bit. And the mineral particle size is the dominant factor affecting the height of weakened layer of rock. Besides, the IDBGM can more fully exert its structural advantages when applied to the hard rock layer with larger particle size. At the same time, the monitored real-time electric current is consistent with the above results, and further reveals the rock breaking mechanism characteristic of the IDBGM. |
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