Penetration and impact resistance of PDC cutters inclined at different attack angles

In order to develop a rotary-percussive bit with diamond-enhanced cutters assisted by high pressure water jets,it is necessary to study the damage mechanism and the penetration properties of PDC cutters subject to different impactload level and rock types. Therefore the impact experiments of the single PDC cutters with different attack angles in fourrocks: black basalt, Missouri red granite, Halston limestone, and a very soft (Roubidoux) sandstone were carried out,and the effects of rake angles of PDC cutters on both the penetration and impact resistance of PDC cutters have been discussed in detail. Test results show that a PDC insert can withstand a very strong impact in compression but is easily damaged by impact shearing, the PDC cutters are more easily damaged by shearing if the attack angles are relatively small, the45 PDC cutters have the least penetration resistance among the cutters tested. Thus it is suggested that the attack anglesof PDC cutters should be larger than 30 for bits which must withstand impact from a hammer