DTH drilling tools have the advantages of high drilling straightness, strong slag discharge ability, smooth hole wall, and easy filling of explosives. Therefore, they are popular in the rock drilling industry. At the same time, as the DTH drilling rig occupies a relatively large market in rock drilling machinery, its development has driven the market demand for DTH drilling tools, especially the demand for medium and high-pressure DTH drilling tools is on the rise.
In the DTH drilling tools, the DTH drill bit directly affects the rock drilling efficiency, which is mainly related to a series of factors such as the end face structure of the DTH drill bit, the shape of the powder discharge groove, the shape and size of the carbide button, and the angle of the gauge button. Therefore, different DTH drill bits should be selected according to different drilling methods and rock types.
Among the above factors, the shape of the end face of the DTH drill bit is directly related to the rock drilling efficiency and service life of the drill bit. Combined with the information on the Internet, the commonly used medium and high-pressure DTH drill bits mainly use five types of end faces: flat drill bits, MF drill bits, convex drill bits, concave drill bits, and rocket drill bits.
Flat drill bit
The drill bit is strong and durable, and is suitable for drilling hard and super-hard rocks, as well as medium-hard and abrasive rocks. The drill bit uses a larger diameter button carbide and has a powder discharge slot in the head to effectively remove rock chips.
MF drill bit
The front center button of the drill bit is conical, the gauge button is spherical button with large air holes and powder discharge slots, and the end face is flat. The drill bit of this shape has a high drilling rate when drilling medium-hard rock and hard abrasive rock.
Convex drill bit
The drill bit adopts a convex structure, uses a large-diameter conical button carbide as the gauge button and front gauge, and is designed with a large powder discharge groove, which has a high rock drilling rate when drilling soft rock and hard rock, and is also suitable for drilling abrasive rock, it is usually more suitable to choose this kind of drill bit when drilling in medium-hard non-abrasive rock formations.
Concave drill bit
The drill bit is available in two shapes, concave structure and concave double gauge button structure, and adopts spherical carbide. The middle part of the end face of the concave structure shape drill bit is a slightly concave conical shape, which is most suitable for drilling rock formations with medium hard and hard rock formations, less abrasive, and broken geological structures, and the deviation of the drilling hole can be well controlled during the drilling process. The concave double gauge button structure shape is used for DTH drill bits with a diameter greater than 203mm. The concave surface of the drill bit with this structure is inlaid with double staggered button alloys and equipped with a reinforced double-gauge button structure, which is suitable for drilling medium-hard and hard rocks with abrasive and faulty geological structures.
Rocket drill bit
This end face shape is used for DTH drill bits with a diameter of 90-115mm, and it has a high drilling rate for soft and medium-hard rock. When drilling medium-hard and abrasive rock, the button bit is used, and the conical button bit is used when drilling soft rock.
