2, punching is the use of impact drilling rigs with drilling edge of the heavy drill bit (also known as punching hammer) to raise, relying on the free-falling impact to cut the rock layer, discharging debris into the hole. There are two types of percussion drilling rigs: drill pipe type and wire rope type. The former drills smaller holes, lower efficiency, less application. The latter drilling diameter is large, according to the design of the pile diameter to modify the size of the drill, hammer weight in 3000kg-10000kg (specifically according to the size of the pile diameter to determine the hammer weight).