The selection of the down-the-hole drilling rig mainly considers several factors: the aperture, depth, direction, angle and drilling accuracy of the engineering hole, the rock condition, the condition of the construction site, the construction period, etc. Then according to these requirements to match the appropriate drilling rig, and supporting its corresponding air compressor. At present, large, medium and small, high, medium and low wind pressure, crawler walking and rubber wheel walking are widely used in the domestic market. The driving power includes diesel engines, electric motors, wind motors and other models. Taking the small and medium-sized crawler walking high wind pressure down-the-hole drilling machine as an example, the analysis is as follows:
1. the power type of down-the-hole drilling rig, the domestic small and medium-sized tracked self-propelled down-the-hole drilling rig mainly has three basic power types:
1. Diesel engine-driven down-the-hole drilling rig: the drilling rig is powered by a diesel engine to drive the hydraulic oil pump group, and the output hydraulic oil is supplied separately:
1) Travel hydraulic motor
2) Swing hydraulic motor
3) Propulsion (lifting) cylinder
4) luffing mechanism cylinder and body floating cylinder.
All actions of the drilling rig are hydraulic, so it is also commonly known as "hydraulic drilling rig".

Advantages:
1) Only the impactor uses compressed air, and the air consumption of the whole machine is small. Air compressors with smaller displacement can be selected, thus reducing the purchase cost of the unit (drilling machine air compressor). It is a kind of development that gradually replaces other power-type drilling machines.
Exhibition products.
2) When the rig is displaced, it can be easily driven away without any drag such as cables and air ducts.
2. Motor-driven down-the-hole drilling rig: Motor-driven drilling rig uses motor instead of diesel engine on the basis of diesel-driven drilling rig, and other basic unchanged.
Advantages:
1) Low air consumption of drilling rig;
2) The dynamic characteristics of the motor are good;
3) Maintenance is simple and maintenance workload is small.
3. All-pneumatic down-the-hole drilling rig: all pneumatic drilling rigs are powered by wind motors, including walking, rotation, propulsion (lifting) oil pumps, and impactors.
Advantages: single power
2. supporting air compressor. In order to achieve high perforation efficiency, the drilling rig with high air pressure air compressor gradually occupies the mainstream position. The main parameters of the air compressor are exhaust pressure and exhaust volume, which should match the design requirements of the drilling rig, which is very important to give full play to the drilling efficiency of the drilling rig. Because the drilling efficiency of the drilling machine mainly depends on the down-the-hole impactor, the amount of air consumption of the impactor is determined by its design structure, and the output power of the impactor increases exponentially with the increase of wind pressure and air volume, and the drilling speed will also increase exponentially. That is to say, when selecting a high-performance drilling rig and a high-efficiency impactor, there must be an air compressor with corresponding air pressure and air volume to ensure, otherwise, the drilling efficiency of the same drilling rig will be greatly different due to the different performance parameters of the air compressor.
In practice, this is often the case: there is already an air compressor, which needs to be matched with a down-the-hole drill; or there is already a down-the-hole drill, which needs to be matched with an air compressor. The main factor to consider is the matching of the down-the-hole drill and the air compressor. Each down-the-hole drilling rig has its specific technical parameters and the requirements of the air compressor, for the construction unit in the purchase of equipment reference.