Polycrystalline diamond compact (PDC) cutters play a key role in the performance of PDC bits in the oil & gas drilling. The study of single cutter on the rock-breaking mechanism is very important for PDC bits to deal with challenging formations, especially when the wells become increasingly longer and complex. Both cutting efficiency and durability are always the focuses of attention for the researches on single PDC cutter. Of all the factors influencing the cutting efficiency, the chamfer is always ignored in theoretical and experimental studies. In this work, the rock-cutter interaction model was modified with considering the effect of the chamfer, which could be used to predict the cutting forces and cutting efficiency of PDC cutters while shearing the rocks. All cutters have been tested on a vertical turret lathe to verify the modified theoretical model. The accuracy of the theoretical prediction agreed well with the experimental results. It was found that the cutting efficiency could be greatly enhanced by reducing the chamfer size for the cylinder-shaped PDC cutters. Unfortunately, the small chamfer size made PDC cutters vulnerable to the premature failure. In order to improve the durability of small-chamfered PDC cutters while retaining their cutting efficiency, an optimized mix of diamond grains was developed and experimentally studied. The results illustrated that the cutter with optimized diamond mix exhibited much better wear resistance. On the other hand, the chamfer size has relatively weak effect on the wear resistance of PDC cutters. The increased chamfer size contributes to protect the cutter edge from chipping but will cause more cumulative friction heat and impair the cutter's durability. The findings in this work will provide a valuable guideline for the manufacturers of PDC bits.

多晶金刚石复合片（PDC）刀具在油气钻探中对PDC钻头的性能起着关键作用。对破岩机理的单刀研究对于PDC钻头处理具有挑战性的地层非常重要，尤其是当井变得越来越长和越来越复杂时。切割效率和耐用性一直是单个PDC切割机研究的重点。在影响切削效率的所有因素中，倒角在理论和实验研究中始终被忽略。在这项工作中，考虑了倒角的影响，修改了岩石与岩石的相互作用模型，该模型可以用来预测PDC岩石在剪切岩石时的切削力和切削效率。所有刀具均在立式转塔车床上进行了测试，以验证修改后的理论模型。理论预测的准确性与实验结果吻合良好。已经发现，通过减小圆柱状PDC刀具的倒角尺寸，可以大大提高切削效率。不幸的是，小倒角尺寸使PDC刀具容易过早失效。为了提高小倒角PDC刀具的耐用性，同时又保持其切削效率，开发了一种优化的金刚石晶粒混合物，并进行了实验研究。结果表明，具有优化金刚石混合的刀具表现出更好的耐磨性。另一方面，倒角尺寸对PDC刀具的耐磨性影响相对较小。增大的倒角尺寸有助于保护切刀边缘免于崩裂，但会引起更多的累积摩擦热并损害切刀的耐用性。这项工作的发现将为PDC钻头制造商提供有价值的指导。