Analysis on the causes of damage and failure of mining cutters

Mining cutters are mainly used for basic excavation such as coal mining and tunnel excavation in mines. So the performance of the cutting teeth directly affects the utilization of coal mining capacity, excavation efficiency, and tool service life. However, there are differences in the quality of mining cutters between China and foreign countries. So analyzing the reasons for the failure of mining cutters is beneficial for reducing the consumption of cutters used in coal mining machines, improving work efficiency, and reducing the labor intensity of underground workers.

When mining cutters work underground, they will encounter hard ores such as coal rods and stones, which will subject the cutters to great pressure and impact loads. In addition, the cutters will experience temperature rise during the coal mining process, causing the material at the top of the cutters to soften and fall off, resulting in the failure of the cutters. The main reasons for the failure of mining cutters are as follows.

（1） Blade damage

When cutting hard coal and rock, the cutting teeth will bear strong impact loads. After repeated impacts, the alloy cutting head will loosen until it falls off, and the cutting teeth will completely fail. During the production process of the cutting teeth, defects such as sand inclusion or virtual welding at the welding points can also cause the alloy head to fall off during use, resulting in the failure of the cutting teeth.

（2） Broken blade tip

The performance of alloys varies greatly, and some alloys may contain graphite impurities with uneven crystal distribution, which can lead to cracks in some alloys and cause the cutting teeth to crack during future use.

（3） Poor wear resistance of alloy head

Cutting gear alloys generally have high drilling content, low density, and low hardness, resulting in poor wear resistance of cutting gear alloy heads.

To improve the performance and service life of cutting teeth, it is necessary to focus on the development of hard alloy cutting heads that are impact resistant, wear-resistant, and crack free, as well as the selection of cutting body materials and the strengthening of welding technology.

� H s =  �@ XAC   style='text-indent:21.0pt'>    A general milling machine consists of an engine, frame, milling rotor, milling depth adjustment device, hydraulic components, aggregate conveying device, steering system, and braking system.

 

 

The milling rotor is the main working component of a milling machine, consisting of a milling rotor shaft, a tool holder, and a tool head. It directly contacts the road surface and works through its high-speed rotating milling cutter to achieve the purpose of milling. The milling machine is equipped with an automatic leveling device, which uses the milling rotor side cover as the milling reference surface to control two positioning hydraulic cylinders to maintain a constant milling depth;

 

Its hydraulic system is used to drive the rotation of milling rotors, the walking of the whole machine, and the operation of auxiliary devices. It is generally a closed hydraulic system with multiple independent pumps, which does not interfere with each other during operation and has high reliability;

 

Some milling machines are equipped with tilt adjusters as needed to control the tilt of the rotor; Generally, large milling machines have an aggregate conveying device consisting of a conveyor belt and a collector. It can concentrate the milled bulk materials and transport them to randomly moving transport vehicles. The height of the conveying arm can be adjusted and can swing left and right to adjust the discharge position.

 

When the specifications and models of milling machines are different, their structures and layouts may also differ slightly, but the basic working principles are the same or similar. The power transmission route of milling machine: engine → hydraulic pump → hydraulic motor, hydraulic cylinder → working device.