Date: 2015-12-5 10:12

In order to achieve the purpose of drilling rocks effectively and fast, DTH bits with high quality and high efficiency should be chosen in high air pressure down-the-hole drilling projects. In other words, DTH bits with different structures should be chosen according to different drilling styles and rock formations. Series of factors including face shapes of bits, shapes of sludge grooves, shapes and dimensions of carbide, hardness of bit bodies and so on have direct influence on drilling rates, quality of drill holes, straightness of blast holes, life time of DTH bits, and work efficiency. Therefore, it is very important to choose suitable DTH bits in drilling projects.
For the high air pressure DTH bits, four main face shapes are most adopted currently, which are convex face, flat face, concave face and drop center face. For the placement of carbide, the even placement of spherical buttons, ballistic buttons or spherical buttons and ballistic buttons are commonly adopted.
1、Convex face: high drilling rates in medium hard to hard abrasive rock, low deviation control, not suitable for drilling projects with high deviation control requirement.
2、Flat face: high firmness and high durability, suitable for hard to very hard rock; also suitable for soft to medium hard rock with low deviation control.
3、Concave face: with a conic concave part in the face to form slight nucleation which maintains centering performance and guarantee high straightness. It is the common face shape in the market and has good flushing effect and drilling rate.
4、Drop center face: with a deep concave center in the middle of face to form slight nucleation with high deviation control in deep holes; but lower face strength than other shapes; only suitable for soft to medium hard rock.