The choice of shape depends on factors such as the nature of the rock and the purpose of the bit. Here are some common bit lip characteristics:
1, rectangular lip: also known as flat bottom, often used for impregnated drill. It is easy to process: it has a very small working area and therefore requires less weight on bit, resulting in a higher rate of penetration with the same drilling parameters. But it goes down to the bottom of the hole when a run-in process, that is, the beginning of the footage is slow, to be ground into a micro arc, only at the normal speed of the footage. Secondly, its stability is poor, easy to cause drilling bending. This lip is commonly used to drill into medium hard and medium abrasive rock formations.
2, circular curved lip: can shorten the initial grinding time, often used for hard, hard and medium abrasive rock.
3, concentric serrated lip: also known as the tip ring groove, diamond is mainly distributed in the tooth part. Large grain size is used inside and outside to ensure bit diameter. The toothed lip can cause the hole bottom with multiple free surfaces, so that the bit can grind and shear the rock, and obtain the coarse-grained rock powder, which is helpful to the diamond cutting edge and improve the mechanical drilling rate. Because the required axial pressure of the bit is small, there is a better anti inclination effect. The serrated lip bit is suitable for drilling into hard, hard, dense and weakly abrasive rock formations.
4, step lip: there are one, two, three steps, usually used for rope coring drill and single tube thick wall drill. This kind of bit has better stability in drilling; The free surface is more and the effect is good when crushing rock. It is suitable for drilling hard rock. At present, it has been used in hard and weak abrasive rock strata and obtained good results.
5. Conical lip: This kind of diamond composite bit has good stability and directivity at the bottom of the hole, which is conducive to anti-skew. Used in wireline coring drills. Conical lip surface can also be divided into inner cone, outer cone, double cone several.
