How to Improve the Service Life of Mining Diamond Roller Cone Drill Bits?

To improve the service life of roller cone bits, in addition to regular storage, transportation, and use of the bits, the following measures should be taken to extend the life of roller cone bits.

Reasonably select the tooth shape of the roller cone bit

Correctly selecting the tooth shape of the roller cone bit can not only extend the life of the bit, but also improve the penetration speed and reduce the cost of drilling. The selection of the tooth shape of the bit mainly depends on the physical and mechanical properties of the rock, namely, the compressive strength, hardness, and drillability of the rock. In addition, the diameter and water content of the borehole and the technical performance of the roller cone drill should also be considered when choosing rock drilling bits for sale.

• When drilling in hard rock formations, we usually use button bits. Since the roller teeth of the button bit have shorter protrusions but denser teeth, they can withstand greater axial pressure and are suitable for drilling in extremely hard and wear-resistant ore.

• When drilling in soft rock formations, we usually use chisel bits with longer roller teeth and sparser teeth, which are suitable for drilling in soft and plastic rocks.
  

If the two are improperly selected, using button bits to drill in soft rock may result in a longer service life of the bit, but the drilling speed of the drill rig is very slow. Considering the drilling cost of the drill rig, the total drilling cost is higher. Therefore, it is important to choose suitable roller cone bit types according to different situations.

On the contrary, if chisel bits are used to drill in extremely hard and wear-resistant ore, the alloy teeth will quickly wear or break. Therefore, a reasonable selection of the tooth shape of roller cone bits can increase the service life of the bits.

Reasonably select the best drilling working system

The drilling speed of the bit is related to many factors, such as the physical and mechanical properties of the rocks being drilled, the axial pressure applied to the bit, the rotation speed of the drilling tool, the torque of the bit, the shape of the roller teeth, the number of teeth involved in breaking the rocks, and the compressed air volume used to flush the borehole. According to the rock crushing mechanism during roller cone drilling, the main parameters that determine the drilling working system are axial pressure, rotation speed, and slag discharge air volume.

The impact of axial pressure on the service life of roller cone bits

To effectively crush the rock, sufficient axial pressure must be applied to the bit so that the stress caused by the teeth of the roller cone can overcome the compressive strength of the rock. However, the applied axial pressure must have a certain reasonable value, that is, it cannot be too large or too small. When the axial pressure exceeds the optimal value to a certain extent, increasing the axial pressure further will not increase the drilling speed. Too much axial pressure will also cause the hard alloy teeth to break or damage the bearings of the bit.

The impact of rotation speed on the bit

Within a certain range, the drilling speed of the roller cone drill rig increases with the increase of the spinning speed of the drilling tool. However, if the speed is too high, it will not only cause difficulties in discharging the borehole bottom, resulting in secondary rock crushing, but also produce strong vibration, affecting the service life of roller cone bits.

The rotation speed of the bit must ensure that the teeth of the roller cone have sufficient contact time with the rock to achieve effective volume crushing of the rock. In hard rock, as the speed increases, the impact load increases, causing significant wear and tear of the roller cone teeth and bearings. Therefore, the use of high speed is limited. However, when the rock is soft, high speed and low axial pressure are usually used.