Many factors affect the efficiency and cost of DTH drilling operations. In addition to rock properties and structures, there are also rock drilling tool structures, the performance of DTH hammers, matching of drilling rig operating parameters, and the level of operators. To obtain a more economical drilling speed, it is necessary to select a suitable DTH drilling tool for different rocks and reasonably match the main working parameters of the drilling rig. Because DTH drill bits are the core product of DTH drilling tools and there are many types, how to choose DTH drill bits often puzzles users.
Types of DTH Drill Bits
The DTH drill bit is connected with the hammer through the spline of the drill bit body and guides and transmits the rotation for the impact, the drill bit and the hammer dive into the hole to break the rock. According to the shape of the drill edge, it can be divided into three types: blade type, column button shape, and blade column mixed type.
1. Blade type drill bit
The blade-type drill bit is a kind of drill bit with welded carbide. The main defect of this kind of drill bit is that the amount of tungsten carbide cannot be reasonably distributed according to the abrasive load. Therefore, the farther the drill edge is from the center of rotation of the drill bit, the greater the load is and the faster the dullness and wear. When the drill edge wears more than 20%, it is easy to stick the drill, and the piercing speed will drop significantly. Therefore, this drill bit is only suitable for small-diameter shallow-hole rock drilling operations.
2. Column button drill bit
The column button drill bit is a drill bit that drills holes in the drill bit body and then embeds a certain number of carbide buttons by cold pressing. This kind of drill bit can self-grinding during the drilling process, the drilling speed tends to be stable, it is convenient to arrange the carbide buttons reasonably according to the stress state, and the embedded process is simple. Therefore, the column button drill bit has been widely used in medium and large-diameter DTH drilling operations.
3. Blade column mixed drill bit
The periphery of the blade column mixed drill bit has a welded edge and the center has a button. This kind of drill bit is designed according to the characteristics of less crushed rock volume in the middle of the bit and larger crushed rock volume in the periphery, which can better solve the problem of excessive wear of the gauge button. The manufacturing process is more complicated, which restricts its popularization and use.
How to choose a DTH drill bit?
When drilling in specific rocks, it is necessary to select a suitable DTH drill bit to achieve high drilling speed and low perforation cost.
Principles for choosing DTH drill bits
1. The specific work of rock drilling in hard rock is relatively large, and each column button and drill bit body bear a large load, which requires the m to have high strength. Therefore, the number of powder discharge grooves of the drill bit should not be too many. Generally, double-wing drill bits are selected, and the size of the powder discharge groove should not be too large, so as not to reduce the strength of the drill body. At the same time, it is best to choose a carbide button and its exposed height should not be too large.
2. When drilling in soft rock with better drillability, the rock drilling speed is faster, and the relative slag discharge volume is relatively large, which requires the drill bit to have a strong slag discharge ability. It is best to choose a three-wing or four-wing type drill bit, the slag discharge groove can be appropriately larger and deeper, the carbide button can be used as a conical button or wedge button, and the button height is relatively high.
3. When drilling in the broken zone with well-developed joints, to reduce the deflection, it is better to choose the middle concave type or the middle convex type drill bit with better-guiding performance.
4. When drilling in clay-containing rock formations, the middle slag discharge hole is often blocked, so it is best to use the side slag drill bit.
5. When drilling in rocks with relatively good toughness, it is best to use wedge-shaped drill bits.
To sum up, the selection principle based on DTH drill bits can help us choose suitable drill bit products, but before that, we still cannot do without the following 4 points.
1. Understand drilling geology
Before selecting a DTH drill bit, it is important to understand the geological conditions of the drilling to be performed. Different terrains and geological environments require different types and sizes of drill bits to achieve optimal results.
2. Select the right drill bit diameter
The diameter of the drill bit must correspond to the geological formation to be drilled. Select the most suitable drill bit diameter according to the specific rock conditions to maximize the rock drilling efficiency.
3. Determine the material of the drill bit
The working environment of the DTH drill bit is very harsh, and the quality of the material directly affects its service life. Therefore, when choosing a DTH drill bit, don’t blindly choose low-priced products, but consider the factors of material and technology comprehensively.
4. Select a high-quality DTH drill bit supplier
A high-quality DTH drill bit supplier should respond on time, provide customized solutions for customers, have high standards for product quality, have a complete service system, and have positive comments from other customers. We are in an era where product homogeneity is becoming more and more serious. Facing a wide range of DTH drill bits and various suppliers, only to choose the most cost-effective DTH drill bit supplier that takes into account both product quality and perfect service.
5. Consider the cost
Cost is one of the significant factors to consider when choosing a down-the-hole drill bit. There are differences in the prices of drill bits of different brands and models, and we should choose the right product according to the project budget. At the same time, we need to consider factors such as the service life of the drill bit.
6. Refer to industry standards and experience
When choosing a down-the-hole drill bit, refer to industry standards and draw on relevant experience. For example, you can learn about the types, brands, and performance of down-the-hole drill bits used in other projects in the same industry, so that you can better choose a down-the-hole drill bit that suits you. In addition, you can also consult professional drilling engineers or technicians for more accurate advice and guidance.
Conclusion
Choosing a suitable down-the-hole drill bit is crucial for improving project progress and efficiency and reducing costs. When selecting a down-the-hole drill bit, you need to understand the type of drill bit, project requirements, rock properties, cost, industry standards, and other factors. Additionally, it’s pivotal to choose high-quality suppliers for cooperation. By making a well-informed selection and using the drill bit appropriately, you can ensure the project proceeds smoothly and achieves good economic benefits.
