What Are The Factors That Affect The Drilling Effect of Hydraulic Rock Drills?

Table of Contents

When drilling rock, the end of the drill rod is impacted by the hydraulic rock drill and propagates in the direction of the rock drill bit in the form of compressive stress waves, and the rock drill bit breaks the rock through the energy transmitted from the drill rod. The hydraulic rock drill is the core component of the hydraulic rock drilling jumbo, and its rock drilling efficiency directly affects the efficiency, application cost, and benefit creation of the hydraulic rock drilling jumbo. Therefore, understanding the factors that affect the drilling performance of hydraulic rock drills can provide a reference for maximizing the work efficiency of hydraulic rock drilling jumbos.

hydraulic tunneling jumbo

Hydraulic rock drill is composed of an impact mechanism, a slewing mechanism, a rotary mechanism, a buffer mechanism, and a lubrication and dust-proof system. It should have four functions of impact, propulsion, rotation, and flushing to complete the impact rock drilling operation, and the result of the combined effect of these four functions under certain conditions is the drilling of the hydraulic rock drill, and they all may affect the drilling efficiency of the hydraulic rock drill in the process.

Influence of rock drilling speed

Many factors affect the drilling speed of a rock drill, such as the impact energy of the rock drill, impact frequency, rotation speed, shaft thrust, rock hardness, drill bit diameter, and shape, and drilling depth, but the main factors are the impact energy, impact frequency, rotation speed, and axial thrust.

The impact power is mainly influenced by the movement speed and impact frequency of the impact piston. The impact frequency is closely related to the movement speed of the impact piston, the faster the movement speed of the impact piston, the higher the impact frequency. Therefore, the movement speed of the impact piston is the decisive factor of the chiseling speed.

Factors Affecting Rock Drilling Efficiency

To improve drilling efficiency, it is necessary to increase the effectiveness of rock breaking to ensure that each impact work can achieve effective rock breaking. Factors that affect the effectiveness of rock breaking are rotation speed, shaft thrust, drill rod, rock drill bit, and whether flushing is sufficient.

rock drilling tools
  • Rotary speed affects the amount of rock broken each time and also affects the amount of rock broken by “rotary shearing”. After a certain number of impacts, it is necessary to rotate the appropriate angle, so that the button on the drill is in a new rock-breaking position to improve the rock-breaking effect. The optimal rotation speed should be determined according to the actual situation, such as rock conditions, drill bit type, drilling depth, and gouge diameter.
  • To achieve high rock drilling efficiency, the rock drill bit must keep good contact with the rock at the bottom of the hole, so a certain axial thrust must be applied to the rock drill. If the axial thrust is too large, the rotary resistance of the drill rod will increase, causing difficulty in rotating the drill rod, reducing the drilling speed, and increasing the wear of the drill bit. If the axial thrust is too small, the drill bit cannot maintain good contact with the bottom rock, rendering the rock breaking ineffective and reducing drilling efficiency.
  • Hydraulic rock drill has a flushing function to remove debris from the borehole. If the flushing is insufficient, repeated crushing will occur during drilling, which will not only reduce the effectiveness of rock breaking but also accelerate the wear of the drill bit and even cause jamming accident
  • Suitable impact rock drilling tools are also important factors in improving drilling efficiency, and matching rock drilling tools, especially drill bits, should be selected according to actual working conditions.


To sum up, there are many factors affecting the effectiveness of hydraulic rock drills, and to ensure the efficiency of rock drilling, we need to determine the best rotation speed and shaft thrust according to the actual working conditions, and to improve the efficiency of rock drilling, we need to choose the matching drill rods and rock drill bits. We can choose a high-quality rock drilling tools supplier for selection advice and support.

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