In engineering construction, rotary drilling rigs are a good helper in foundational construction and often encounter different geological conditions. The rotary drill bit and cutting teeth are critical components that directly impact the rock layer, affecting construction efficiency, costs, and project quality. How to choose a rotary drill bit is crucial to the working performance of a rotary drilling rig.
Introduction to Common Rotary Drill Bits
Cylinder bit: Suitable for gravel layers, can encase and remove gravel; also appropriate for large diameter solitary rocks or hard formations.
Double-bottom sand bucket: Used for granular formations such as sand and silt, effective in scooping sand, very useful in thick sand layers.
Auger bit: Used for clay and silty clay, its auger structure conveniently cuts into and lifts soil debris; commonly used in shallow, small diameter piles with soft cohesive soils.
Two-piece bit: Suitable for formations containing mixed clay and sand, can effectively grab and crush clumps.
A high-quality rotary drill bit not only excels in drilling but also features guiding, self-protection, high slag discharge efficiency, and easy slag unloading. Some rotary drill bits also need to have hazard prevention and fishing functions. For composite formation construction, if the diameter allows, a suction hole prevention function can also be designed, integrating multiple advantages.
Characteristics of Rotary Drill Bits
Drilling
All rotary drill bits are almost entirely designed around the drilling function. Whether cutting, crushing, or grinding, the ultimate goal is the same: drilling. Therefore, improving drilling performance and reducing resistance are core issues in drilling.
Guiding
Even with high drilling capability, if the pile is skewed, no matter how fast the pile is driven, it's useless. Not only does it become problematic to inspect the hole, but it also poses various hazards such as rod binding, stuck drilling, and binding cage.
Guiding part: The pilot tip has a positioning guiding function, but attention should be paid to the height, width, and type of the pilot tip. Increasing the pilot tip height enhances the guiding function but also increases resistance; a pilot tip that's too low loses its guiding function and doesn't reduce resistance.
Protection
While drilling into harder formations, if there are defects in the rotary drill bit, the defect positions will quickly become apparent, accelerating the wear rate. These defect positions also contribute to increased resistance. Thus, a good rotary drill bit should consider self-protection in its design.
Protection parts: Pilot tip type, combination of pilot tip and drilling teeth, drilling teeth angle, drilling teeth spacing, drilling teeth position, cutting sequence, protective bars, etc.
Slag Carrying and Unloading
The double-bottom sand bucket is the most commonly used rotary drill bit. This is due to its strong slag carrying and unloading capabilities, making it suitable for various geological constructions.
Some bits, such as the cone spiral bit, are only suitable for dry holes and require high-speed soil flinging. In the case of slurry static pressure piles, the limited slag carrying capacity and difficult slag unloading significantly reduce construction efficiency.
Hazard Prevention
The double-bottom sand bucket has both conical and cylindrical forms. The conical design can enhance guiding and reduce resistance during lifting, but it also has potential hazards. Debris or stones falling into the gap between the conical body and the hole wall can cause the drill to jam. The cylindrical body provides better drilling guidance but is slightly inferior to the conical body in preventing suction and unloading slag.
Suction Hole Prevention
Particularly when drilling into silt layers, due to the fluid plasticity of silt, suction can occur during lifting, causing shrinkage and collapse of the hole.
Suction parts: If the diameter of the rotary drill bit allows, install a guide channel inside the drill body or open a fan-shaped slot at the bottom of the drill body and install side knives. Pay attention to the single bucket depth and the starting point of lifting; additionally, the channel can increase slurry circulation during lifting, reducing resistance. Or adopt a D-shaped bucket structure design to form an external guide channel.
Why Choose Rotary Drill Bits for Sale from EXCELLENT?
The rotary drill bits for sale from EXCELLENT are an important part of rotary drilling rigs, mainly used to quickly and accurately complete excavation tasks and pile foundation construction through high-speed rotation and powerful digging force.
The rotary drill bits for sale from EXCELLENT can be categorized based on their cutting angles and blade configurations into: 90-degree U-shaped roller bits, 120-degree U-shaped roller bits, star-shaped roller bits, etc.
Additionally, EXCELLENT offers customized rotary drill bits to meet the different needs of customers.
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