High-frequency impact drilling speed-up theories and its tools have rapid developed in recent year

and effectively solve the problem of the stick-slip

rebound and vibration of PDC (polycrystalline diamond compact) bit in complex wellbore. However

the failure of PDC teeth under impacting load remains serious. For this reason

a new type of drill bit combining of separated impact and cutting is proposed

this drill bit can effectively solve the adverse effect of impact load on the service life of PDC teeth. The rock breaking of the drill bit is totally different from that of traditional percussion tools

and the mechanism of the rock breaking is unclear

it is thus urgent to perform relevant study. Based on the new type of drill bit combining of separated impact and cutting

the rock breaking experiments under different combinations of unit tooth impact

cutting and their different combinations are carried out

and the corresponding numerical analysis is carried out. The results show that the rock with significant impact pit is damaged by the shock wave after the impact tooth loading

consequently

reducing the strength of the rock around impact pit. As a result

it also effectively reduces the cutting force of the cutting teeth during cutting

and increases the crushing volume. At the same time

based on the orthogonal experiment

the parameter sensitivity analysis is carried out considering the impact speed

the impact angle and the offset distance between the impact pit and the cutting tooth. The results show that the impact speed has the greatest influence on the cutting force of the cutting tooth. The above research reveals the mechanism of rock breaking under combining of separated impact and cutting and the best combination of impact tooth and cutting tooth. The present work has important reference value for the design and research of impact drilling tools.