Latest developments

17

2022

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03

What is the matter with the stuck drill in the rock drilling operation of the rock jumbo?

The drill is a drill that the drill is stuck in the hole during the rock drilling operation and cannot work. Chuck is a common problem. Chuck will reduce work efficiency and increase the consumption of drill bit, drill rod, drill tail and hydraulic rock drill parts.



 

What is the sticking of the drill in the rock drilling operation of the 1. jumbo?

The drill is a drill that the drill is stuck in the hole during the rock drilling operation and cannot work. Chuck is a common problem. Chuck will reduce work efficiency and increase the consumption of drill bit, drill rod, drill tail and hydraulic rock drill parts.

 

What is the cause of 2. clamping?

1. Complex rock conditions will cause jamming

If the rock conditions are complex, such as cracks, intercalation, and drastic changes in geological conditions, it is easy to cause sticking. In case of complex geological conditions, close attention should be paid to the working state of rock drilling, and the working parameters of rock drilling jumbo should be adjusted in time to reduce jamming.

2. Caused by the cause of the drill

(1) Excessive wear of the column tooth drill bit causes jamming

Generally, new drill bits or newly ground drill bits are tapered from head to tail. When drilling holes in abrasive rocks (high quartz content), the wear around the drill bit gradually makes the positive cone become an inverted cone, and the drill bit is excessively worn, causing sticking.

(2) Design and selection of drill bit

The surrounding rock is very abrasive (high quartz content), and the regular designed column tooth bit alloy is quickly worn out, resulting in jamming. In this case, the design type of the column tooth drill bit should be adjusted in time, and the inclination angle of the edge tooth should be appropriately increased. At the same time, the column tooth drill bit should be ground in time to replace the severely worn column tooth drill bit.

The design of column tooth drill bit is not suitable for surrounding rock, especially the small diameter column tooth drill bit such as 43mm and 45mm column tooth drill bit, which causes poor powder discharge during rock drilling operation and is easy to cause jamming. The drill bit with better powder discharge effect should be adjusted in time according to the characteristics of the rock, and the drill bit should be ground in time to reduce the jamming.

3. Cause of rock drilling jumbo jamming

(1) Setting problem of anti-jam pressure of rock drilling jumbo

If the anti-sticking pressure setting value of the anti-sticking device of the rock drilling jumbo is too high, sticking will occur frequently. Only when the sticking pressure is greater than the pressure set value of the anti-sticking device, the anti-sticking device will respond when the sticking occurs, so that the rock drill can realize reverse feed, pull out the drill bit, and release the sticking.
(2).Effect of drilling and flushing powder discharge

If the flushing water pressure is too low, it may cause poor flushing effect of the rock hole, retain a large amount of rock slag, increase the friction force when the drill bit is drilling, thus causing the rotation resistance to rise, and the drill bit may be stuck in the rock hole.

(3). Improper selection of hydraulic oil

Improper selection of hydraulic oil can also cause sticking. By the hydraulic oil viscosity temperature: the higher the temperature, the smaller the hydraulic oil viscosity; the lower the temperature, the greater the hydraulic oil viscosity. In the case of low ambient temperature, the hydraulic oil temperature will be lower, at this time the hydraulic oil viscosity increases, it may make the rotary resistance more than the normal drilling rotary pressure, resulting in sticking.

The exclusion method of 3. stuck drill

(I), if the phenomenon of sticking occurs frequently during drilling, first consider adjusting the pressure setting value of the anti-card device. The rotary pressure of the anti-card device action (switch the advancing direction at this time) should be set to 15 standard atmospheres higher than the normal drilling advancing rotary pressure value. The setting of anti-jamming pressure must be accurate, not too high or too low, too high, sticking will occur frequently; If it is too low, the rock drilling rig cannot work normally (at this time, the anti-jamming pressure is less than the normal working pressure of the rock drilling rig, and the anti-jamming device has been activated before the rig reaches the normal working pressure, so that the rock drilling rig cannot drill normally).

(II), in the unfractured rock mass, the phenomenon of sticking occurs frequently. If it is not the problem of the set value of the anti-sticking pressure, it is the signal of grinding the drill bit, with special emphasis on the surrounding grinding to restore the taper. The drill bit becomes blunt due to wear, which will inevitably affect the drilling efficiency and increase the rotary resistance during drilling. If the rotary resistance exceeds the normal drilling rotary pressure, the drill will be stuck. In addition, under the condition of maximum pushing pressure, the reduction of rotary pressure is also a sign that the drill bit needs to be ground. The shape of the button should be ground to restore the convex height of the button from the plane of the drill bit body. Therefore, it is very important to grind the drill bit regularly and restore the taper of the drill bit.
(III), if the drill bit is stuck in the rock gap, the anti-card device cannot eliminate the stuck drill, the rotary pressure can be increased, the push handle is placed in the reverse feed position, and the drill rod and drill bit can be pulled out.
(IV). If the rock slag in the rock hole is not washed well, the washing water pressure should be checked first, and the washing water pressure should be appropriately increased to improve the slag washing effect.
(V), if the anti-jamming pressure is set correctly, the rock is free of cracks, the bit taper is appropriate, and the flushing effect is good, but there is still a sticking phenomenon, it is necessary to consider whether the viscosity of the hydraulic oil is correct. If the oil temperature is too low, take appropriate measures to raise the oil temperature, and replace the hydraulic oil with appropriate viscosity if necessary.