(1) Impact energy and impact frequency

　　To improve the ROP, the impact energy and impact frequency should be increased. However, in the pneumatic impactor of the DTH hammer, impact power and impact frequency are two parameters that restrict each other. To increase the impact power, it is necessary to increase the stroke of the piston, which will reduce the impact frequency. Conversely, to increase the impact frequency, it is necessary to reduce the weight of the piston and the stroke of the piston, which in turn reduces the impact energy.

　　(2) Fissure water on the perforation face. This is mainly for the drilling face with crevice water. Taking Dulong Manjiazhai Mine as an example, there is often water on the working surface during the perforation process, which will greatly reduce the power of the perforation operation. In the long run, the long-term existence of fissure water will increase the equipment failure rate of the DTH hammer.

　　(3) Wind pressure. The impactor of the DTH drill is a pneumatic tool. To achieve the rated impact energy and impact frequency, wind pressure is an important factor. Increasing the wind pressure can adjust the effect of slag removal, improve the ROP, and improve the lives of the drill bit. When the wind pressure increases from 0.7Mpa to 1.4Mpa, the perforation speed increases by 70%. It is for this reason that the large-bore DTH hammers are now equipped with air compressors to reduce pipeline pressure drop.

　　(4) Drilling diameter. Increasing the bore diameter, in turn, increases the piston diameter of the impactor, which increases impact energy and impact frequency. On the other hand, increasing the diameter of the borehole can increase the mesh parameters of the blasting, and increase the linear meter blasting amount of the borehole and the annual perforation amount of the drilling rig.

　　(5) Preparation of the perforation surface. The cleaning and selection of the working surface is also an important factor affecting the perforation speed. The working surface is not flat, and the drilling rig cannot perforate according to the planned parameters; the soft rock on the working surface is not cleaned, which affects the perforation speed and the quality of the orifice. Therefore, the preparation of the work surface is very important.

　　(6) Axial pressure and rotational speed. The axial pressure of the DTH hammer is mainly to overcome the recoil of the impactor, so the pressure is generally not large, much smaller than the axial pressure of the roller cone drill. Excessive axial pressure not only hinders the reversal of the drill but also easily damages the drill bit. For the DTH hammer with a large aperture and heavyweight, decompression drilling is generally used due to the large weight of the drilling rig, that is, the advancement of the drilling rig should play a role in reducing the axial pressure. Small, often used to promote the organization as a supercharged push. If the reverse rotation speed of the DTH hammer is too low, the piercing speed will be reduced, but if the rotation speed is too high, the drill bit will be worn out due to excessive speed, which will also reduce the piercing speed. Now, in hard rock drilling, the low speed tends to be used, which is kept at 16~20r/min. Of course, with the emergence of high-pressure, high-frequency, and large-impact impactors, the reversal speed of the drilling tool will also increase accordingly.