What is roller bit and how to choose and use it?

The rotary roller bit is a key component of the rotary drilling rig. It directly contacts the stratum and plays the role of crushing and cutting soil and rocks. As the main working part of the rotary drilling rig, the performance of the roller bit directly affects the progress and quality of the project.

The rotary roller bit is usually composed of a wheel body, cutting teeth, bearings and other parts. The cutting teeth are the key components of the roller bit. They directly act on the stratum to play the role of crushing and cutting. The bearings are responsible for support and transmission to ensure that the roller bit can run smoothly.

Material: The materials used to make the rotary roller bit are usually high-quality materials such as high-strength alloy steel. These materials have excellent strength and wear resistance, and can withstand the high pressure and friction generated during the rotary drilling process while maintaining a long service life.

Manufacturing process: The manufacturing process of the rotary roller bit usually includes casting, forging, heat treatment and other links. Exquisite manufacturing technology can ensure the dimensional accuracy and surface quality of the roller bit, reduce stress concentration and early wear caused by manufacturing defects, thereby improving its load-bearing capacity and service life.

Characteristics of rotary drilling roller bit:

- Strong load-bearing capacity: rotary drilling roller bits usually have strong load-bearing capacity and can withstand the high pressure and friction generated during rotary drilling. Its load-bearing capacity varies depending on the model, material and working conditions, and the general load-bearing range ranges from several thousand pounds to tens of thousands of pounds.

- Good wear resistance: The roller bit is usually made of high-quality materials such as high-strength alloy steel, has good wear resistance, and can maintain a good cutting effect during long-term use.

- Strong adaptability: rotary drilling roller bits can adapt to different geological conditions and engineering needs, and are widely used in pile foundation construction, foundation pit support, underground continuous wall, mineral exploration, hydrogeological exploration, reservoir dam construction, embankment reinforcement, bridge pier foundation construction, and subway tunnel construction.

Type:

Rotary drilling rollers can be divided into many types according to their structure and usage requirements, such as single roller, double roller, and three rollers. Among them, the rows of teeth on the three-roller drill bit mesh with each other, which can prevent the tooth grooves from sticking and improve the drilling efficiency.

According to the tooth shape, roller drill bits can be divided into the following categories:

- IADC517: low compressive strength, high drillability soft formations, such as shale, clay, sandstone, soft limestone, etc.

Cutting tooth structure: large diameter skewed top spoon-shaped inner row teeth, wedge-shaped outer row teeth. High tooth exposure, unequally spaced teeth, main and auxiliary teeth double bottom hole crushing line cutting structure.

- IADC537: low compressive strength, medium soft, with harder abrasive interlayers, such as hard shale, hard gypsum, soft limestone, sandstone, interlayer dolomite, etc.

Cutting tooth structure: large diameter skewed top spoon-shaped inner row teeth, wedge-shaped outer row teeth. High tooth exposure, unequally spaced teeth, main and auxiliary teeth double bottom hole crushing line cutting structure.

- IADC617.627: High compressive strength, medium hardness, thick hard interlayers, such as hard shale, limestone, sandstone, dolomite, etc.

Cutting tooth structure: large arc spoon-shaped inner row teeth, wedge-shaped outer row teeth, unequally spaced teeth, main and auxiliary teeth double bottom hole crushing line cutting structure.

- IADC637.647: High compressive strength, medium hardness and highly abrasive formations, such as limestone, dolomite, sandstone flint, etc.

Cutting tooth structure: conical inner row teeth, spherical outer row teeth, main and auxiliary teeth double bottom hole crushing line cutting structure.

- IADC737.837: Hard formations with high abrasiveness, such as hard limestone, dolomite, hard sandstone, flint, etc.

Cutting tooth structure: large arc conical inner row teeth, spherical outer row teeth, and an additional row of trimming teeth between the back cone teeth and the outer row teeth.

Usage and maintenance of roller bits

1. Precautions for installing cone drill bits

- Drum wall opening size: The width of the cylinder wall opening should be just suitable for placing the tooth claw or base to avoid leaving too large a gap. The opening depth should be such that the welded cone is exposed to 1/2 to 2/3 of the wheel height of the cylinder wall, and ensure that the cylinder walls on both sides of the cone are chamfered.

- Installation order of cone palms: Follow the principle of alternating positive and negative and three-wheel complementation to ensure the stability and durability of the drill bit.

- Welding process: When welding the cone palm or base, ensure that all cone palms are at the same level and located on the same circle. At the same time, when welding, the principle of tilting the cone 5°~7° to the back of the claw should be followed to avoid tilting to the wheel tip to reduce the wear of the claw tip. In addition, cooling measures should be taken during welding, such as immersing the cone palm in water for staged welding reinforcement to prevent high temperature from damaging the seal ring or bearing lubrication system.

2. Precautions during using

- Load control: The load range of each cone palm is usually 3 to 5 tons. During use, the barrel drill should be ensured to be within the pressure range to avoid damage to the drill bit due to overload.

- Drilling monitoring: During use, the drilling situation should be closely monitored. If drilling abnormalities are found, the drill bit usage should be checked in time and corrected in time to avoid unnecessary damage.

- Hole bottom rock treatment: When encountering strongly weathered rock formations or hard rock formations, a suitable cone drill bit should be selected for drilling, and the drilling parameters should be adjusted according to the hardness of the rock to ensure drilling efficiency and drill bit life.

3. Maintenance and care

- Regular inspection: After each use, the rock chips and sediments in the protective barrel should be removed in time, and the wear of the cone palm and the support point should be checked. If damaged, it should be repaired or replaced in time.

- Lubrication and cleaning: Lubricate and clean the drill bit regularly to reduce wear and extend its service life.

- Storage management: When the drill bit is not in use, it should be properly stored to avoid moisture, corrosion or damage.