Diamond bit used in drilling reinforced concrete structure

Due to reinforce concrete's high strength grade and embedded rebar, it is difficult to obtain an efficient drilling result during the repair and renovation constructions.Besides diamond bit cutters are usually broken during the drilling process, thus leading to diamond bit's short service life.To solve those problems, regulating bit matrix property, optimizing diamond bit structure, as well as adding grinding types are employed within this study.Soft-medium hardness matrix and cubic boron nitride which improves the cutting performance of abrasive particles on the diamond bit workface are used to increased the drilling rate.Optimized bit structures, including diagonal water gap and asymmetric cutters are employed for ensuring a steady drilling process.It can avoid the suddenly full-face encounter between bit cutters and the rebar, which may produce huge transient impact load and cause cutters breaking.Test results indicate that, the average drilling rate and total service life of ϕ75 mm diamond bit are 1.12 m/h and 28 m respectively under the optimized drilling parameters (i.e., the drilling pressure of 6.5 MPa, linear velocity of 2.1m/s and coolant flow of 25 L/min) and there is no cutters broken during the drilling test.Consequently, the diamond bit design methods in this study are proved to be correct, and the diamond bits manufactured following those methods and technologies can satisfy the requirements of construction.