Factors affecting the efficiency of rock drilling tools
The efficiency of rock drilling is not only related to the correct selection of hard joint numbers, but also influenced by many factors, mainly including the shape of the drill head, rock hardness, compressed air pressure, powder discharge method, borehole diameter and depth, etc.Drill head shape:The shape of the drill bit directly affects the cross-section of the borehole. Most drill hole sections for rock drilling are polygonal rather than circular. So the formation of a polygonal cross-section is due to the deviation of the drill head towards the side of the gun limit when it rotates along its own axis. During rock drilling, the drill rod does not rotate on a fixed axis, but freely swings in the hole of the gun. This situation can be seen through careful observation in actual supply. The shape of the drill bit varies, and the cross-section of the borehole obtained during rock drilling also varies.The edge shape of the borehole section is the number of blade blades used plus one. When using a large diameter drill bit to drill rock, the phenomenon of non circular hole shape is more significant. The non circular shape of the hole will increase the breakage of the fundus and the length of the surrounding area, while the rocks around the fundus are the most difficult to break. Therefore, it will greatly affect the drilling speed. The non circular shape of the hole can also hinder the normal rotation of the drill bit. For deep hole drilling, the impact is even greater, and it can even cause twisting and breaking of the drill rod or causing jamming. In recent years, research has been conducted to find solutions to the effects caused by non circular hole shapes. For example, changing the shape of the drill bit, thickening the thickness of the working edge, and increasing wind pressure. But it has not been completely resolved and further research is needed.
