Rock drilling tools play a vital role in rock engineering. However, various wear and tear phenomena often occur during use, which affects work efficiency and cost control. To ensure the normal operation and long service life of the equipment, it is essential to study the reasons for the loss of rock drilling tools and prevent them.
Reasons for the loss of rock drilling tools
Rock drilling tools are not concentric
The lack of concentricity between the shank adapter, the coupling sleeve, and the drill rod causes the bending deformation of rock drilling tools to generate stress, which leads to the mismatch of the joint of rock drilling tools and the loosening of the connection part.
The propulsion pressure does not match
- If the pressure is too low, the penetration efficiency of rock drilling will be reduced, causing the combination to loosen, causing the energy loss transmitted by the rock drilling tool, causing high stress, and causing the instantaneous contact and separation of the contact joint end surface. Rock drilling tools heating is a sign of insufficient propulsion pressure, the “clack” sound at the joint, overheating makes the thread wear abnormally, and corrosion pits appear.
- The pressure is too high, the rotation speed of the drill bit is low, there is a danger of the drill sticking, and the bending stress of the drill rod increases.
Impact pressure
If the impact pressure is not appropriately adjusted, it will directly affect the rotary speed, rock drilling efficiency, and rock drilling tools’ service life.
Rotation speed
The rotary speed should match the drill bit diameter and the rock drill impact frequency. The bigger the drill bit is, the lower the rotary speed is, and too high a rotary speed will damage the periphery of the drill bit.
Rotary pressure
The normal rotary pressure is very critical. It provides proper anti-seize protection for drill rods and ensures a definite rotary pressure. The increase in rotary pressure is critical to maintain the tightness of rock drilling tools. If the tightness is not enough, it often causes heating at the joint, peeling off the thread surface, early wear, or even breakage of the thread.
Improper use
If the rock drilling tool is used with the new rock drilling tool, it will shorten the service life of rock drilling tools. In addition, the connecting rod is not centering, there is sand on the thread, and the rock drilling tool is easily damaged if the thread is not lubricated. “Empty striking” is the most damage to the rock drilling tool and should be avoided as much as possible.
Other factors
- Frequent rock drilling operations will make the rock drilling tool’s surface wear, and long-time use will easily cause fatigue rupture, resulting in damage.
- Rock hardness, structure, and particle size will affect the wear of rock drilling tools. Harder rocks will wear the rock drilling tools faster.
- The humidity, temperature, and other conditions of the working environment will also affect the loss of rock drilling tools. Humid conditions may accelerate rust and corrosion.
Precaution
Regular maintenance
Clean and lubricate the rock drilling tools in time, check for wear, cracks, and other problems, and ensure a comprehensive inspection before use.
Correct operation
Train operators on the correct use method, reasonably control the impact force and angle, and avoid excessive force unnecessarily.
Choose the suitable rock drilling tools
Choose the appropriate material and type of rock drilling tools according to the rocks’ characteristics to improve wear resistance and fatigue resistance.
Improve working environment
Keep the working environment as dry and stable as possible to reduce the possibility of corrosion of rock drilling tools.
Regular replacement
Set a reasonable rock drilling tools’ replacement cycle to avoid the long-term use of old rock drilling tools and reduce the risk of fatigue fracture.
The loss of rock drilling tools is inevitable. With reasonable operation and maintenance measures, it can effectively reduce the loss rate, prolong the service life of the equipment, and improve the working efficiency, thus providing strong support for the smooth progress of rock engineering. The operator must follow the operation manual during use and take corresponding measures immediately when the loss is higher or abnormality is detected to ensure the safe and stable operation of the equipment.
