DTH button bits are widely used in mining, quarrying, water conservancy engineering, water wells, railway, and highway construction due to their high efficiency, safety, environmental protection, simple structure, and ease of operation.

The working principle of  DTH button bits involves transmitting stress impact waves generated by DTH hammers to continuously high-frequency impact the rock surface. The rock cracks and breaks under the impact, and is directly cut off under the rotary action of the DTH drill pipe. And with the action of high-pressure airflow, the broken rock cuttings is continuously blown out of the hole, thereby achieving the purpose of drilling.

During the drilling process, the carbide buttons of DTH button bits mainly bear the high-frequency stress waves from DTH hammers, directly transmitting the high-frequency stress waves to the rock surface and participating in the cutting work. The carbide buttons of DTH button bits experience very complex stress conditions during operation, making it particularly important to choose the right button shape.

Commonly used carbide button shapes of DTH button bits include conical buttons, ballistic buttons, semi-ballistic(parabolic) buttons, and hemispherical(dome) buttons.

1. Conical Buttons

Conical buttons have a sharp shape, so they have a small contact area with rock, less resistance, and faster drilling speed. However, due to their slimmer volume, the carbide buttons have relatively poor bending and torsion resistance. The exposed buttons height is relatively high after inserting, which can generate significant bending moments during operation, making the carbide buttons easy to breaking.

The greatest advantage of conical buttons is their fast drilling speed, suitable for all soft rocks and low-abrasive rock formations.

2. Ballistic Buttons

Ballistic buttons evolved from conical buttons, enhancing the structural flaws of conical button shapes, effectively improving the bending and torsion resistance of the carbide buttons, thereby extending the button life. They also combine the advantages of conical buttons, achieving fast drilling speeds.

Ballistic buttons are most suitable for soft rock, medium-soft rock, and low-abrasive rock formations. They offer faster drilling speed and higher rock-breaking efficiency than hemispherical buttons, but they are not very suitable for broken rock formations, as they may break easily.

3. Semi-ballistic (Parabolic) Buttons

Semi-ballistic buttons have a fuller shape compared to ballistic buttons, making them more wear-resistant. These button shapes balance the durability of hemispherical buttons with the high rock-breaking speed of ballistic buttons, suitable for medium-hard or medium-abrasive rock formations.

4. Hemispherical (Dome) Buttons

Hemispherical buttons possess excellent bending and torsion resistance, unmatched in impact toughness and strength compared to other button shapes. Due to their fuller crown, the allowable wear on carbide buttons is relatively increased, extending the service life significantly. 

They are widely used in various working air pressures, various rock hardness geological structures, especially in high air pressure fields exceeding 1.6MPa and complex geological environments with interlayers and cracks.  However, the carbide buttons have a large contact area with the rock surface when working, generating high friction resistance, thus resulting in a slower drilling speed.

Hemispherical buttons are the most commonly used shape in DTH drill bits and are most suitable for hard rock and highly abrasive rock formations.

Each shape of carbide buttons has its own scope of use and work characteristics. When selecting, clients should consider factors such as rock hardness, geological structure, and engineering requirements to choose the suitable button shape to ensure smooth progress of the drilling project!