Nowadays, underground rock drilling equipment occupies an increasingly important position in mine production and construction. With the continuous expansion of project scale and the development of mining machinery manufacturing industry, backward rock drilling equipment can no longer adapt to the needs of underground mine development, and new rock drill jumbo gradually becomes the main equipment for mechanized rock drilling. Hydraulic tunneling jumbo is one of them.

1. What is a Hydraulic tunneling jumbo?

Hydraulic tunneling jumbo is a high-efficiency rock drilling machine used in construction projects such as large underground metal mine roadway excavation, tunnel excavation, power station engineering diversion tunnel, underground powerhouse construction, and underground rock anchor hole drilling.

With the advancement of drilling and blasting technology, hydraulic tunneling jumbo is increasingly showing its superiority in engineering construction, and its usage is also increasing, which makes the demand for matching rock drilling tools increase. Drill rod is one of the main supporting tools for hydraulic tunneling jumbo and is consumed in a large amount in rock excavation.

2. Drill rods

Rock drilling tools consisting of a single rod are usually used when hydraulic tunneling jumbo is working. Drill rods in the form of R32/R28-H25-R25, R32-H28-R25/R28, T38/R38-H32-R32, and T38/R38-H35-R32 are mainly used.

Since drill rod of hydraulic tunneling jumbo is a slender rod, the shape of rod is usually hexagonal, because it has a larger cross-sectional area and better bending strength compared with a round rod.

3. Rock drill bits

Rock drill bits used in hydraulic tunneling jumbos are mainly button bits with 35-51 mm in diameter. To make hydraulic tunneling jumbo achieve the purpose of fast rock drilling, it is required that the button bit has a series of performance characteristics such as strong toughness and good wear resistance of button, high strength of steel body of rock drill bit, effective rock breaking by button arrangement. In addition, location of flushing water hole and powder discharge slot to adapt to the rapid exclusion of rock chips.

In a word, the main requirements for rock drilling tools in the use of hydraulic tunneling jumbo are high toughness and strength, good wear resistance of drill rod, fast drilling speed of rock drill bit, smooth powder discharge, wear resistance of button, and not easy to jam the drill, etc.

In industrially developed countries, it is very common to use hydraulic tunneling jumbos for underground engineering construction. Therefore, internationally famous rock drilling tools production companies attach great importance to research and development of improving the performance of rock drilling tools and have made great progress in the improvement of product material performance and structure form. It can be said that in the two decades from the early 1980s to the beginning of this century, shape and structure of products have been improved at least three times, and each improvement brings improvement in product performance.

As we all know, impact power output by a rock drill is driven by a drill rod to drill into the rock. A drill rod is not only a component of rock drilling tools but also a carrier of rock drilling energy in the form of stress waves. In energy transmission, change in the cross-section of drill rod and defects on the surface or inside of steel are the parts where stress is concentrated, and they are also the parts that easily cause drill rod to fracture. Therefore, problem of how to reduce the stress concentration at the root of thread of drill rod, especially at the root of thread at the end of connecting bit end, has received attention from rock drilling tools companies since the 1980s.

Nowadays, the rapid development of mechanical and hydraulic equipment technology makes hydraulic tunneling jumbos develop in the direction of high-impact power. Market demand is bound to be more and more stringent for matching rock drilling tools. Therefore, it is important to pay attention to research and selection of raw materials and technology for production enterprises of rock drilling tools.