The DTH drill bit is a drill tool connecting the hammer with the spline of the drill bit to guide and transmit the rotation and impact energy, which dives into the hole to break rock with the drill bit and hammer. It is mainly used in large open-pit mines, underground ore mining, anchoring engineering, quarrying, construction engineering, and large-scale construction engineering. There are four types of face designs for DTH drill bitsDTH drill bits used in production.
Deep concave center type
A deep concave center type is an end face with a recessed center section. The nucleation at the center of the depression makes it the best of all face designs for maintaining borehole straightness. Due to the presence of a deep inner surface discharge groove, deep concave center drill bits are somewhat weaker than other shapes in strength. It is only suitable for drilling soft and medium hard rocks.
Concave type
Concave drill bits have a slightly conical depression on the bit face. It is best suited for general use. Due to the light nucleation effect of the concave face, it helps to keep the hole straight and provides excellent drilling speed and good chip removal for all formations. It is the most used end-face design on the market.
Flat type
Flat drill bits have a flat, continuous end face. Due to its simple shape, it is the strongest and most durable of all drill bits. It is best suited for use in fractured or very hard rock formations and is also suitable for use in soft formations where the deflection of the borehole is not a preferred requirement. There is usually no discharge groove on the end face of the flat drill bit, so compared with the concave drill bit, the drilling speed and the straightness of the hole are affected to a certain extent. Increasing the discharge groove on the end face can improve chip removal ability and drilling speed, but its strength is weakened. This drill bit is not well suited for drilling into overburdened formations or any application where the straightness of the borehole is critical.
Convex type
Convex drill bits were developed for drilling into very hard and abrasive rock formations where the bit and gauge buttons are prone to wear due to cuttings carried by the airflow across the bit face. This drill bit has two rows of carbide gauge buttons arranged on two separate prongs, with the inner row of buttons assisting the outer ones to prevent excessive wear. To further increase the wear resistance, the carbide buttons of the bit are usually of large diameter.